CN105954508A

CN105954508A - A test sensor used for measuring the concentration of an analyte in a sample

Info

Publication number: CN105954508A
Application number: CN201610245321.7A
Authority: CN
Inventors: 埃米·H·楚; 伍焕平; 朱伯儒
Original assignee: Bayer Healthcare LLC
Current assignee: Bayer Healthcare LLC
Priority date: 2008-12-08
Filing date: 2009-12-07
Publication date: 2016-09-21

Abstract

The invention provides a test sensor used for measuring the concentration of an analyte in a sample. The test sensor comprises at least two conductors, one conductor being a working electrode, and a reagent composition arranged on or near the working electrode. The reagent composition has an average reagent composition surface area and contains adhesive, buffer salt with a concentration of 9.54nmol at most for every mm<2> of the reagent composition surface area, and a fixator with a concentration of 4.76nmol at most for every mm<2> of the reagent composition surface area, wherein the fixator contains at most 20% (w/w) of inorganic nontransition metal salt, an enzyme system, a non-ionic surface active agent and an ionic surfactant. The biological sensor can provide shorter analysis time and desired accuracy and/or precision.

Description

For measuring the test sensor of the analyte concentration in sample

The application is filing date December in 2009 07 day, invention entitled " for bio-sensing Low total salt reagent composition of device and system " Application No. 200980147993.2 patent application Divisional application.

The reference of related application

This application claims in entitled " the less salt reagent composition of December in 2008 submission on the 8th (Low-Salt Reagent Composition) " U.S. Provisional Application No.61/201,242 preferential Power, is incorporated herein its full content as reference.

Background technology

Biosensor provides such as whole blood, serum, blood plasma, urine, saliva, interstitial or thin The analysis of the biofluids such as intracellular fluid.Generally, biosensor has and leaves test in for analyzing The measurement apparatus of the sample on sensor.Sample is typically liquid, and can be biofluid or The derivant of biofluid, such as the precipitate of extract, dilution, much filtrate or rehydration.Biological What sensor performed analyze measures one or more analytes existence in biofluid and/or dense Degree.The example of analyte include alcohol, glucose, uric acid, lactate, cholesterol, bilirubin, Free fatty, triglyceride, protein, ketone, phenylalanine or enzyme.This analysis is permissible Physically different for diagnosing and treating.Such as, diabetics can use biosensor to survey Determine the glucose level in whole blood, and this information may be used for adjusting diet and/or the use of patient Medicine.

Biosensor can be designed to analyze one or more analytes, and can use not Same sample volume.It is 0.25-15 that some biosensors can analyze a whole blood, such as volume The whole blood of microlitre (μ L).Biosensor can utilize the measurement apparatus such as desk-top, portable to implement. Portable type measurement unit can be hand-held, and can analyze one or more in sample Thing is identified and/or quantifies.The example of Portable type measurement unit includes: be available from Tarrytown, The Ascensia of the Bayer HealthCare of New YorkWithMeasuring instrument；And platform The example of formula measurement apparatus includes: be available from the electrification of the CH Instruments of Austin, Texas Learn work station.There is shorter analysis time, there is desired accuracy and/or degree of accuracy simultaneously Biosensor be that user provides huge benefit.

In electrochemica biological sensor, by the analyte when input signal being applied to sample or In response to the signal of telecommunication produced by the oxidation/reduction reaction of material of analyte or redox reaction Measure analyte concentration.Input signal can be as single electric pulse or multiple-pulse, sequence or follow The form of ring applies.Can add in the sample the oxidoreductasees such as such as enzyme or the like with Strengthen during redox reaction electronics from the first material to the transfer of the second material.Enzyme Or the like can react with a kind of analyte, thus to produced output signal Part provides specificity.

Electrochemica biological sensor generally includes measurement apparatus, and measurement apparatus has and test sensing The electric contact that electric conductor in device connects.Test sensor can external, internal at Living Organism Or the internal use of part.When in Living Organism external use, the sample of biofluid is introduced and surveys In sample reservoir in examination sensor.Can introduce before sample for analysis, after or during the period Test sensor is placed in measurement apparatus.When in Living Organism body or when part is internal, permissible Continuously test sensor is soaked in the sample, or test sensing can be introduced the sample into off and on In device.Test sensor can include the reservoir being partially isolating certain volume sample, or surveys Examination sensor can open to sample.Similarly, sample can flow continuously through test sensor or It is interrupted to be analyzed.

For electrochemica biological sensor, conductor can be by such as solid metal, metal paste, conduction Carbon, the conduction conductive materials such as carbon paste and conducting polymer are made.Electric conductor generally and extends to sample Working electrode, antielectrode, reference electrode and/or other electrodes in reservoir connect.One or Multiple electric conductors can also extend in sample reservoir to obtain the function that electrode is not provided that.

Can utilize in such as United States Patent (USP) No.6,531,040,5,798,031 and 5,120,420 etc. Described multiple technologies form test sensing by arranging on insulating body or printing electrode Device.Can be by arranging that on one or more conductors one or more reagent compositions form electricity Pole.Such as, when working electrode and antielectrode are coated with by same composition, the conductor more than Can be coated with by reagent composition of the same race.Multiple technologies well known by persons skilled in the art may be used for Reagent composition is arranged on test sensor.Reagent composition can be arranged as reagent fluid On conductor, then it is dried.When sample is introduced into test sensor, reagent composition starts again Hydration.

Different reagent compositions can be arranged on conductor.Thus, the agent combination of working electrode Thing can contain enzyme, amboceptor and binding agent, and the reagent composition of antielectrode then contains can be with work Make the identical or different amboceptor of the amboceptor of electrode and binding agent.Reagent composition can be containing being used for Promote analyte oxidation or the ionizer such as such as oxidoreductase of reduction and contribute to analyte and Any amboceptor of the electron transfer between working electrode or other materials.Except for reagent is bonded Outside together, such as, binding agent can help erythrocytic filtration, prevent erythrocyte at conductor Stablizing of coating on surface and oxidoreductase.

Obtaining output signal from test sensor the fastest, that has analyzed is the fastest, wherein in test Sensor accurately can be measured analyte concentration from output signal.Thus, when there is shorter analysis Between, there is the bio-sensing containing reagent composition of desired accuracy and/or degree of accuracy simultaneously Device can be that user provides huge benefit.

The measurement performance of bio-sensor system is defined in terms of accuracy and/or degree of accuracy.Accuracy And/or the raising of degree of accuracy can improve the measurement performance of system.Accuracy can be expressed as sensor The analyte reading of system is relative to the deviation of reference analyte reading, and deviation value is the biggest, represents standard Exactness is the lowest.Degree of accuracy can be expressed as the deviation exhibition relative to meansigma methods of multiple analyte reading Degree or variance.Deviation refers to the analyte concentration from the biofluid that bio-sensor system is measured One or more values and one or more reference value adopted between difference.Thus, measure and divide One or more errors in analysis can cause the inclined of the analyte concentration recorded of bio-sensor system Difference.Deviation can be expressed as " absolute deviation " or " deviation % ".The unit table that absolute deviation can be measured Showing, such as mg/dL, and deviation % can be expressed as the absolute deviation values percentage ratio relative to reference value. Reference instrument can be used to obtain the reference value adopted, such as, derive from YSI Inc., Yellow Springs, The YSI 2300STAT PLUS of Ohio^TM。

Bio-sensor system can provide in the biological fluid analysis include one or more errors Output signal.Such as, do not respond when one or more parts or the whole output signal of output signal In or during undeservedly in response to the analyte concentration of sample, these errors may be in abnormal output Signal reflects.These errors can come from one or more contribution factors, such as the thing of sample Reason characteristic, the environment aspect of sample, the operating condition of system, interfering material etc..The physics of sample Characteristic includes hematocrit (erythrocyte) concentration etc..The environment aspect of sample includes temperature etc..System Operating condition include the most enough conditions when sample size is the biggest, slowly the filling of sample, sample Intermittent electrical contact between product and one or more electrodes of test sensor and analyte phase interaction The decomposition etc. of reagent.Interfering material includes ascorbic acid, uric acid, acetaminophen etc.. There may be other contribution factors or the combination of contribution factor causing error.

Many bio-sensor systems include that one or more correct the side of the error relevant with analysis Method.The concentration value obtained from the analysis with error may be inaccurate.Thus, correct these and forbidden The ability really analyzed can improve the accuracy of the concentration value of acquisition.Error correcting system can compensate One or more errors, as being different from the sample temperature of reference temperature or being different from reference to hemocyte ratio The sample hematocrit content of capacitance.Such as, conventional biosensor system can be configured to On the premise of the hematocrit content of hypothesis whole blood sample is 40% (v/v), report that glucose is dense Degree, regardless of sample actual hematocrit content how.In such systems, for containing Any glucose measurement carried out less than or greater than the blood sample of 40% hematocrit all will include Error, and thus there is the deviation owing to hematocrit effect.

Therefore, persistently need the bio-sensor system improved, particularly can improve in sample The accuracy of analyte concentration measurement and/or those bio-sensor systems of degree of accuracy.Additionally, need Want to provide shorter and shorter analysis time, provide desired accuracy and/or degree of accuracy simultaneously Improvement bio-sensor system.The system of the present invention, apparatus and method overcome and standard biologic At least one shortcoming that sensing system is relevant.

Summary of the invention

The invention discloses the biosensor system of a kind of analyte concentration for measuring in sample System, it include redox reaction for being optionally analyzed thing reaction part and for Measure the measurement parts of the redox reaction speed of analyte.Described reaction part contains binding agent； Buffer salt；The amboceptor of the inorganic nontransition metal salt containing at most 20% (w/w)；With enzyme system.Described Measure parts and include at least two conductor.Described measurement parts are introducing the sample into described reacting part Measuring the output signal value under maximum power performance at most 7 seconds of part, wherein said output is believed Number value is in response to the analyte concentration in sample, and described measurement parts determine in response at least one At least one Δ S value of error parameter.Described measurement parts are also from including that at least one is with reference to dependency The analyte concentration in sample, wherein said benefit is measured with the equation that compensates of described at least one Δ S value Repay the R of equation²Value is at least 0.5.

The invention discloses the test sensor of a kind of analyte concentration for measuring in sample, its Including: at least two conductor, one of them conductor is working electrode, and is arranged in described work electricity Extremely go up or reagent composition near it.Described reagent composition has average reagent composition surface Amass and containing binding agent；Concentration is every mm²Described reagent composition surface area at most 9.54nmol Buffer salt；Concentration is every mm²The amboceptor of described reagent composition surface area at most 4.76nmol, Wherein said amboceptor contains the inorganic nontransition metal salt of at most 20% (w/w)；Enzyme system；Nonionic table Face activating agent；And ionic surface active agent.

The invention discloses the test sensor of a kind of analyte concentration for measuring in sample, its Including: there is the reservoir of reservoir volume；At least two conductor in described reservoir, its In a conductor be working electrode；And it is arranged in the agent combination on described working electrode or near it Thing, described reagent composition contains binding agent；Concentration is reservoir volume at most 67 described in every μ L The buffer salt of nmol；Concentration is the amboceptor of reservoir volume at most 40nmol described in every μ L, its Described in amboceptor contain the inorganic nontransition metal salt of at most 20% (w/w)；Enzyme system；Non-ionic surface Activating agent；And ionic surface active agent.

The invention discloses the test sensor of a kind of analyte concentration for measuring in sample, its Including: at least two conductor, one of them conductor is the working electrode with working electrode area, And it is arranged in the reagent composition on described working electrode or near it.Described reagent composition contains Binding agent；Concentration is every mm²The buffer salt of described working electrode area at most 167nmol；Concentration For every mm²The amboceptor of described working electrode area at most 100nmol, wherein said amboceptor contain to The inorganic nontransition metal salt of many 20% (w/w)；Enzyme system, nonionic surfactant；With ion table Face activating agent.

A kind of method that the invention discloses analyte concentration for measuring in sample, comprising: Aqueous specimen containing at least one analyte is introduced to reagent composition, uses described aqueous specimen Make described reagent composition rehydrated；Applying input signal between conductor, described sample is at described point Analyse thing, electric connection is provided between described reagent composition and described conductor；With from one or more defeated Go out signal value and measure the concentration of one or more analytes in described sample, wherein containing described Water sample measures output signal value from described conductor in being introduced at most 7 seconds of described reagent composition. Described reagent composition has average reagent composition surface area and can contain binding agent；Exist Concentration is every mm²The buffer salt of described reagent composition surface area at most 9.54nmol；Exist dense Degree is every mm²The amboceptor of described reagent composition surface area at most 4.76nmol；Enzyme system；With non- Ionic surface active agent.

A kind of method that the invention discloses analyte concentration for measuring in sample, comprising: Produce at least one output signal value in response to the analyte concentration in sample, determine from least one Plant at least one Δ S value of error parameter, with at least one with reference to dependency and at least one Δ S value Compensate at least one output signal value described, and from least one output signal pH-value determination pH described Analyte concentration in sample.

The invention discloses a kind of reagent fluid for forming reagent composition, it contains water；Viscous Mixture；There is concentration and be at most the buffer salt of 115mM；There is concentration and be at most Jie of 90mM Body, wherein said amboceptor contains the inorganic nontransition metal salt of at most 20% (w/w)；Enzyme system；With non- Ionic surface active agent.The pH of described fluid can be 4.5～7.5.

Accompanying drawing explanation

The present invention be may be better understood in conjunction with figure below and explanation.Ingredient in accompanying drawing Need not draw according to ratio, but focus on explaining the principle of the present invention.

Figure 1A is the axonometric chart of the test sensor through assembling.

Figure 1B is the top view of the test sensor that the lid of Figure 1A has removed.

Fig. 2 is the end-view of the test sensor of Figure 1B.

Fig. 3 represents for measuring the existence of analyte in the sample contacted with low total salt reagent composition And/or the electrochemical analysis method of concentration.

It is 400mg/dL that Fig. 4 illustrates for concentration of glucose and hematocrit is the whole blood of 70% Sample carrys out the output signal of self-test sensor.

Fig. 5 A illustrates have the test sensor of the reagent composition listed in table 1 and containing 50 Mg/dL glucose also has the time to peak that the blood sample of varying level hematocrit contacts Figure.

Fig. 5 B illustrates have the test sensor of the reagent composition listed in table 1 and containing 100 Mg/dL glucose also has the time to peak that the blood sample of varying level hematocrit contacts Figure.

Fig. 6 A is shown in has after the test sensor of reagent composition A contacts with sample 5 seconds Time the Δ S of sample that measures_totalThe dependency graph changed than index (simple ratio index) with letter.

Fig. 6 B is shown in has after the test sensor of reagent composition B contacts with sample 5 seconds Time the Δ S of sample that measures_totalWith letter than the dependency graph of index change.

Fig. 6 C is shown in has after the test sensor of reagent composition C contacts with sample 5 seconds Time the Δ S of sample that measures_totalWith letter than the dependency graph of index change.

Fig. 6 D is shown in has after the test sensor of reagent composition D contacts with sample 5 seconds Time the Δ S of sample that measures_totalWith letter than the dependency graph of index change.

Fig. 6 E is shown in has after the test sensor of reagent composition E contacts with sample 5 seconds Time the Δ S of sample that measures_totalWith letter than the dependency graph of index change.

Fig. 7 illustrates that the test sensor with the reagent composition listed in table 1 is at 21.8 DEG C R²It is worth the diagram with the change of chemical examination time.

Fig. 8 illustrates that low total salt reagent composition F and G R5/4 at 16 DEG C indexes with hemocyte The diagram of specific volume level change.

Fig. 9 illustrates that the analyte utilizing gating current input signal to measure in the sample of biofluid is dense The schematic diagram of the biosensor of degree.

Detailed description of the invention

The invention discloses a kind of reagent composition testing sensor, it has than test sensing Total salt of the conventional reagent compositions lower concentration of device.Including in low total salt reagent composition is delayed Rush the total concentration of the salt of salt and inorganic nontransition metal salt, can be the total of salt in conventional sensors The half or less of concentration.Low total salt reagent composition can contain nonionic surfactant, also Ionic surface active agent can be contained.

Output signal from the test sensor including low total salt reagent composition can be in wide scope Hematocrit in the most relevant to the analyte concentration of whole blood sample.Relative to agent combination For having the conventionally test sensor of the total salt of higher concentration in thing, this is the biggest improvement, conventional Test sensor can provide accurately measurement in the hematocrit of more close limit.

Output signal from the test sensor including low total salt reagent composition can be at about 7 seconds Interior the most relevant to the analyte concentration of sample.Relative to reagent composition has higher concentration For the conventionally test sensor of total salt, this is the biggest improvement, and conventionally test sensor may need The output signal the most relevant to the analyte concentration of sample was provided more than 7 seconds.

Figure 1A and Figure 1B illustrates test sensor 100.Figure 1A is the test sensor through assembling The axonometric chart of 100, it includes sensor base 110, and this sensor base is at least in part by lid 120 cover, and also include vent 130, sample footprint 140 and input opening 150.Part The reservoir 160 closed is formed between base portion 110 and lid 120.Other can also be used to survey Examination sensor design.

By inserting the liquid into opening 150, analysis fluid sample can be transferred to reservoir In 160.Liquid is filled in reservoir 160, is discharged by vent 130 simultaneously and had previously contained Air.Reservoir 160 can contain the reservation compositions that helpful fluid sample is retained in reservoir (not shown).The example retaining compositions includes that such as the water such as carboxymethyl cellulose and Polyethylene Glycol expands Property polymer and the such as porous polymer such as dextran and polyacrylamide substrate.

Figure 1B is the top view of the test sensor 100 that lid 120 has removed.Conductor 170,180 Working electrode 175 can be connected to respectively with anti-from measurement apparatus interface 155 below dielectric layer 190 Electrode 185.Working electrode 175 and antielectrode 185 can the most at grade, as it can be seen, Or (not shown) in Different Plane.Working electrode 175 and antielectrode 185 can be with lids 120 Top separate at least 100 μm.Dielectric layer 190 can partly cover electrode 175,185, and And can be made up of any suitable dielectric materials such as such as insulating polymers.

Antielectrode 185 can support that testing the electrochemistry at the working electrode 175 of sensor 100 lives Property.By forming antielectrode 185 from inert substance (such as carbon) and making dissolvable redox material (such as iron cyanide amboceptor) is included in reservoir 160, thus will support at working electrode 175 The current potential of electro-chemical activity is supplied to sensing system.Current potential at antielectrode 185 can be logical Cross the reference potential forming antielectrode 185 from redox couple (such as Ag/AgCl) and obtain, thus Reference-the antielectrode of combination is provided.Selectively, test sensor 100 can be provided with the 3rd conductor With electrode (not shown), with to sensing system provide reference potential.

The area of working electrode 175 can be with the area equation of antielectrode 185, an or electrode Area can be more than the area of another electrode.At present, it is preferred to, working electrode area is little In antielectrode area.Preferably, antielectrode area and working electrode area ratio are at least 1, more excellent Choosing at least 1.1, more preferably at least 1.2, more preferably at least 1.3, more preferably at least 1.4, more preferably At least 1.5.

Fig. 2 is the end-view of the test sensor of Figure 1B, it is shown that working electrode 175 and antielectrode The Rotating fields of 185.Conductor 170,180 can be arranged directly on base portion 110.Surface conductor layer 270,280 optionally can be arranged on conductor 170,180.Surface conductor layer 270,280 Can be made by with the identical or different material of conductor 170,180.

Can include appointing for forming the material of conductor 170,180 and surface conductor layer 270,280 What electric conductor.Preferably electric conductor is non-ionized so that material will not during sample analysis There is clean oxidation or only reduce.Conductor 170,180 preferably includes the thin layer of metal paste or metal, example Such as Au Ag Pt Pd, copper or tungsten.Surface conductor layer 270,280 preferably comprise carbon, gold, platinum, Palladium or a combination thereof.If there is not surface conductor layer on conductor, then conductor is preferably by unionized material Material is made.

Surface conductor material can be by any usual manner cloth compatible with the operation of test sensor Put on conductor 170,180, including paper tinsel deposition, chemical gaseous phase deposition, paste deposition etc..At slurry In the case of material deposition, such as, such as United States Patent (USP) No.5, described in 798,031, can be as oil Mixture is coated on conductor 170,180 by ink.

Reagent composition 275,285 can be arranged on conductor 170,180 or near it. Term " ... upper (on) " be defined as " ... above " and be for described direction 's.Such as, if the first element deposition the second element at least some of on, then write as " One element is deposited on the second element ".In another example, if the first element is positioned at second yuan Part at least some of above, then write as " the first element is on the second element ".Use term " ... On " time be not precluded from there is also material between described upper element and lower element.Example As, the first element can have coating on its top face, and the first element and Topcoating thereof are extremely A few part the second element above can be write as " on the first element ".Therefore, term is used " ... on " two relevant element physical contacts or non-physical contact can be represented.

Reagent composition contains reagent and binding agent.Binding agent contains at least one being substantially dissolved in water Polymeric material and be optionally substantially insoluble in the porous particle of water.Porous particle can be polymer Material provides extra physical arrangement.Binding agent can form gel or gel when being hydrated by sample Shape material.Optional layer 290 can be arranged on conductor 170 and/or surface conductor layer 270.Optional Layer 290 can lack one or more compositions of reagent composition 275.

Reagent composition 275,285 can be containing identical or different reagent.When containing identical examination During agent, reagent composition 275,285 can be identical compositions.When containing different reagent, Reagent can be selected for working electrode 175 present in the first compositions 275, and second Present in compositions 285, reagent can be selected for antielectrode 185.Such as, compositions 285 In reagent can containing promote electronics free-pouring amboceptor between sample and conductor 180.With Sample, the reagent in compositions 275 can be containing promoting the enzyme system of analyte response and optional amboceptor.

The enzyme system comprised in reagent composition 275 can have specificity, and enzyme system to analyte The reaction of analyte can be promoted, strengthen the sensing system specificity to analyte, especially simultaneously In compound bio sample.Enzyme system can containing participate in analyte redox reaction one or Multiple enzyme, cofactor and/or other parts.Such as, alcohol oxidase can be used for providing alcohol in sample The sensitive test sensor of existence.This system is applicable to measure blood alcohol concentration.At another In example, glucose dehydrogenase or glucoseoxidase can be used for providing to be deposited glucose in sample At sensitive test sensor.Such as, this system can be used for measuring known or doubtful suffers from glycosuria The sick blood sugar concentration in patient.

Reagent composition 275,285 can be appointed by such as printing, liquid deposition or inkjet deposited etc. What convenient manner is arranged.Such as, one or more reagent fluids can be deposited on test sensor On, and reagent fluid can be dried and form reagent composition 275,285.In test sensing The example of the apparatus and method depositing reagent fluid on the electrode of device is disclosed in such as applies for artificial Boru In the U.S. Patent Application Publication US 2009/0145756A1 of Zhu et al..

Various factors may affect the size of the reagent composition 275,285 obtained.These factors Example include the viscosity of reagent fluid used, screen mesh size and Emulsion combination and its on deposit examination The characteristic size of the sensor of agent fluid.When the most relatively thin reagent composition, it is possible to use print Method outside brush, such as micro-pipette method, ink-jet method or needle pin method.These methods generally produce micro- Rice or the dry reagent composition of submicron thickness, such as 1-10 μm.Such as, needle pin method can provide about The reagent composition of 1 μm average thickness.By the thickness of reagent composition produced by needle pin method such as Can be controlled by the amount of the binding agent comprised in reagent composition, binder content is the highest, reagent set Compound is the thickest.

Each composition in reagent composition (such as 275,285) can be determined relative to the size of compositions Amount, or these compositions can the most thereon the sensor of arrangement combinations thing another kind of size come Quantitatively, such as reservoir volume or working electrode area.In one example, reagent composition is each Composition can be scaled every square millimeter of (mm²) microgram (μ g) of reagent composition surface area, nanogram (ng), nanomole (nmol) or enzyme unit (U) come quantitatively, wherein reagent composition surface area refers to examination The two-dimensional areas of agent compositions.In another example, each composition of reagent composition can convert Microgram (μ g), nanomole (nmol) or enzyme unit (U) for every microlitre (μ L) reservoir volume are come quantitatively. In another example, each composition of reagent composition can be scaled every square millimeter of (mm²) work The microgram (μ g) of electrode area, nanomole (nmol) or enzyme unit (U) are come quantitatively.

Reagent composition preferably comprises binding agent.Water suitably it is substantially soluble in as binding agent Polymeric material may include that poly(ethylene oxide) (PEO), carboxymethyl cellulose (CMC), polyethylene Alcohol (PVA), hydroxyethylene cellulose (HEC), hydroxypropyl cellulose (HPC), ethyl-hydroxyethyl Cellulose, carboxymethylethylcellulose, polyvinylpyrrolidone (PVP), polyamino acid are (the most poly- Lysine), PSS, gelatin, acrylic acid, methacrylic acid, maleic anhydride, Its salt, its derivant and combinations thereof.Polymeric material includes monomer, prepolymer and can be formed Repetitive or there is the other materials of repetitive.Other polymeric materials can also be used.

In these polymeric materials, PEO, PVA, CMC and HEC are preferred, HEC It is the most preferred.For HEC, weight average molecular weight (M_w) to be about 8,000～1,000,000 be excellent Choosing, M_wBeing about 15,000～500,000 is it is furthermore preferred that M_wBeing about 90,000～300,000 is Preferred.At present, M_wIt is about HEC and M of 90,000_wThe HEC's of about 300,000 Mixture is particularly preferred.

The preferably every mm of reagent composition²Reagent composition surface area contains the viscous of about 0.14～0.43 μ g Mixture, more preferably contains about 0.17～0.38 μ g/mm²Binding agent, more preferably contain about 0.22～0.35 μg/mm²Binding agent.The preferably every μ L reservoir volume of reagent composition contains the viscous of about 1～3 μ g Mixture, more preferably contains the binding agent of about 1.2～2.6 μ g/ μ L, more preferably contains about 1.5～2.3 μ g/ μ L Binding agent.The preferably every mm of reagent composition²Working electrode area contains the bonding of about 1～7.5 μ g Agent, more preferably contains about 1.2～6.5 μ g/mm²Binding agent, more preferably contain about 1.5～5.7 μg/mm²Binding agent.

Reagent composition is optionally with the porous particle being substantially insoluble in water.Preferably, if many Hole granule is present in reagent composition, then the ratio between porous particle and binding agent is maintained at About 1:10 (w/w).Other ratios may be used for the performance that reagent composition provides different.Reagent The example of the porous particle of compositions is disclosed in the U.S. Patent application such as applying for artificial Boru Zhu Announce in 2009/0178936A1.

Reagent composition preferably comprises buffer salt.When reagent composition contacts with aqueous specimen, slow Rushing salt preferably keeps the pH value of mixture to be about 4.5～7.5, more preferably from about 6～7.Examination can be selected The preferable ph of agent compositions and buffer salt are to keep the activity of enzyme.Phosphate-based buffer agent is current Preferably, but other buffers can also be used.Preferably, buffer salt includes Na₂HPO₄。

The preferably every mm of reagent composition²Reagent composition surface area contains about 2.30～9.54nmol Buffer salt, more preferably contains about 2.80～6.43nmol/mm²Buffer salt, more preferably contain about 3.40～4.77nmol/mm²Buffer salt.The preferably every μ L reservoir volume of reagent composition contains about The buffer salt of 16～67nmol, more preferably contains the buffer salt of about 20～45nmol/ μ L, more preferably Buffer salt containing about 24～34nmol/ μ L.The preferably every mm of reagent composition²Working electrode area Containing about 16～the buffer salt of 167nmol, more preferably contain about 20～113nmol/mm²Buffering Salt, more preferably contains about 24～84nmol/mm²Buffer salt.

Reagent composition can be containing the single or double electron mediator being substantially dissolved in water.Electricity based on them Chemism, amboceptor is segmented into two classes.Single electron transfer amboceptor is the condition in electrochemical reaction The chemical part of an extra electron can be obtained down, and bielectron transfer amboceptor is the bar in reaction The chemical part of two extra electrons can be obtained under part.The example of single electron transfer amboceptor includes all As 1,1 '-dimethyl ferrocene, ferrocyanide and the iron cyanide and hexamine close ruthenium (III) and hexamine Close the compounds such as ruthenium (II).

Although other amboceptors can be used, but bielectron transfer amboceptor can be preferably as with Single electron transfer amboceptor is compared, and in the case of identical amboceptor mole, they can be by about 2 times Electronics be transferred to working electrode from enzyme system.Thus, compared with single electron transfer amboceptor, at reagent Compositions can use lesser amount of bielectron shift amboceptor.Such as, bielectron shifts amboceptor Amount can be the half of single electron transfer amboceptor amount.

The example of bielectron transfer amboceptor includes organic quinone and hydroquinone, such as luxuriant and rich with fragrance quinoline quinone；Phenothiazine and Phenazene derivative；3-(phenyl amino)-3H-azophenlyene；Phenothiazine；With 7-hydroxyl-9,9-dimethyl -9H-acridine-2-ketone and derivant thereof.Preferably bielectron transfer amboceptor includes 3-phenylimino -3H-phenothiazine (PIPT) and 3-phenylimino-3H-azophenlyene (PIPO).Preferred bielectron turns Move amboceptor and include carboxylic acid or the salt of phenothiazine derivative, such as ammonium salt.At present, particularly preferred double Electron transfer amboceptor include (E)-2-(3H-phenothiazine-3-yldeneamino) benzene-1,4-disulfonic acid, (E)-5-(3H-phenothiazine-3-yldeneamino) M-phthalic acid, (E)-3-(3H-phenothiazine-3-subunit ammonia Base)-5-carboxyl ammonium benzoate and combinations thereof.The example of other bielectrons transfer amboceptor includes United States Patent (USP) No.5,393,615, electroactive organic molecule described in 5,498,542 and 5,520,786.

Bielectron listed above transfer amboceptor can be containing inorganic nontransition metal salt as impurity. Inorganic nontransition metal salt is typically sulfate radical [SO₄]^2-Alkali metal or alkali salt.Such as, (E)-2-(3H-phenothiazine-3-yldeneamino) benzene-1,4-disulfonic acid can contain inorganic nontransition metal salt As impurity, inorganic nontransition metal salt is 1%～50% relative to the mass percent of amboceptor (w/w), such as 3%～30% (w/w), 4%～25% (w/w) and 5%～21% (w/w).

The preferably every mm of reagent composition²Reagent composition surface area contains about 1.70～4.76nmol Amboceptor, more preferably contains about 2.30～5.14nmol/mm²Amboceptor, more preferably contain about 2.80～4.00 nmol/mm²Amboceptor.The preferably every μ L reservoir volume of reagent composition contains about 12～40nmol Amboceptor, more preferably contain the amboceptor of about 16～36nmol/ μ L, more preferably contain about 20～28 The amboceptor of nmol/ μ L.The preferably every mm of reagent composition²Working electrode area contains about 12～100 The amboceptor of nmol, more preferably contains about 16～90nmol/mm²Amboceptor, more preferably contain about 20～70 nmol/mm²Amboceptor.The preferably every mm of reagent composition²Reagent composition surface area contains at most The amboceptor of 4.76nmol, every μ L reservoir volume contains the amboceptor of at most 40nmol, or every mm² Working electrode area contains the amboceptor of at most 100nmol.

Reagent composition is possibly together with the enzyme system being substantially dissolved in water.The enzyme system of reagent composition uses Preferred enzyme include: alcoholdehydrogenase, lactic acid dehydrogenase, beta-hydroxy-butanoic acid dehydrogenase, glucose-6- Phosphate dehydrogenase, glucose dehydrogenase, formaldehyde dehydrogenase, malic dehydrogenase and 3-hydroxy kind are solid Alcoholdehydrogenase.Preferably enzyme system is independent of oxygen, is not aoxidized by oxygen.

A kind of enzyme family being independent of oxygen is glucose dehydrogenase (GDH).Use different coenzyme or auxiliary The factor, GDH can be mediated by different amboceptors differently.According to the association feelings with GDH Condition, the cofactor such as such as flavin adenine dinucleotide (FAD) (FAD) can be fastened by apoenzyme, such as, exist In the case of FAD-GDH；Or, the cofactor such as such as pyrro-quinoline quinone (PQQ) (PQQ) can be with master Enzyme is covalently bound, such as in the case of PQQ-GDH.In enzyme system of each of these enzyme systems Cofactor can be fixed by apoenzyme or coenzyme, apoenzyme can enzyme system is added to reagent fluid it Front reconstruct.Coenzyme can also be added in the apoenzyme part of reagent fluid independently, to help apoenzyme Catalysis, such as in nicotinamide adenine dinucleotide NAD/NADH⁺Or nicotinamide adenine Dinucleotide phosphoric acid NADP/NADPH⁺In the case of.

The preferably every mm of reagent composition²Reagent composition surface area contains about 0.07～0.3 active unit The enzyme system of (U specifies according to manufacturer), more preferably contains about 0.09～0.25U/mm²Enzyme system, More preferably contain about 0.1～0.2U/mm²Enzyme system.The preferably every μ L reservoir volume of reagent composition Containing the enzyme system of about 0.5～1.8U, more preferably contain the enzyme system of about 0.6～1.6U/ μ L, more preferably contain There is the enzyme system of about 0.8～1.4U/ μ L.The preferably every mm of reagent composition²Working electrode area contains about The enzyme system of 0.5～5U, more preferably contains about 0.6～4U/mm²Enzyme system, more preferably contain about 0.8～3.5 U/mm²Enzyme system.

Reagent composition preferably comprises nonionic surfactant.Surfactant can contribute to Formed and there is desired viscosity and the colloidal suspensions of stability and hold concurrently with deposition process and analysis Any nonionic surfactant held.The example of nonionic surfactant includes living in saccharide surface Property agent, such as N-heptanoyl group-N-METHYL-ALPHA-L-GLUCOSAMINE, N-caprylyl-N-methyl-glucamine, N-pelargonyl group -N-METHYL-ALPHA-L-GLUCOSAMINE, N-capryl-N-METHYL-ALPHA-L-GLUCOSAMINE, octyl group β-D-glucopyanoside, oneself Base β-D-glucopyanoside and n-heptyl β D-glucopyanoside.At present, such as N-caprylyl -N-methyl-D-glucosamine (sell as MEGA 8, can from DOJINDO, Gaithersburg, MD obtain) etc. sugar surfactants be preferred.Such as, this surfactant per molecule bag Include about 8 ethylene oxide units.Other preferred surfactants are based on ethoxylate Neutral surface active agent, if PEG-30 tetramethyl decynediol surfactant is (such as, from Air The SURFYNOL 485 that Products, Allentown, PA obtain).The sample of sensor can be improved Filling rate and/or the surfactant contributing to stable enzyme system are preferred.

The preferably every mm of reagent composition²Reagent composition surface area contains the non-of about 0.04～0.24 μ g Ionic surface active agent, more preferably contains about 0.07～0.21 μ g/mm²Nonionic surfactant, More preferably contain about 0.09～0.18 μ g/mm²Nonionic surfactant.Reagent composition is preferred Every μ L reservoir volume contains the nonionic surfactant of about 0.3～1.7 μ g, more preferably contains about The nonionic surfactant of 0.5～1.5 μ g/ μ L, more preferably contain about 0.6～1.3 μ g/ μ L non-from Sub-surface activating agent.The preferably every mm of reagent composition²Working electrode area contains about 0.3～4.3 μ g Nonionic surfactant, more preferably contain about 0.5～3.8 μ g/mm²Non-ionic surface active Agent, more preferably contains about 0.6～3.2 μ g/mm²Nonionic surfactant.

Reagent composition is optionally with anion surfactant.Surfactant can be to help In formed reagent composition the periphery accurately limited and with deposition process and analyze any of compatibility Anion surfactant.The example of anion surfactant includes phosphate ester, such as polyoxyethylene Alkyl phenol phosphate ester；Sulfate, such as polyoxyethylene alkylphenol sulfate；And sulfonate, such as alkyl With miscellaneous alkylsulfonate.The object lesson of anion surfactant includes polyoxyethylene nonylphenol phosphorus Acid esters Phospholan CS131 and Phospholan CS141, polyoxyethylene nonylphenol sodium sulfate (Witcolate D-51-53), sodium methyl cocoyl taurate (Geropon TC-42) and dioctyl sulphur Change sodium succinate.

The preferably every mm of reagent composition²Reagent composition surface area contains the moon of about 3～16 nanograms (ng) Ionic surface active agent, more preferably contains 4～12ng/mm²Anion surfactant, more excellent Choosing is containing 5.5～9ng/mm²Anion surfactant.The preferably every μ L of reagent composition preserves Device volume contains the anion surfactant of about 20～140ng, more preferably contains 30～80ng/ μ L Anion surfactant, more preferably contain the anion surfactant of 35～60ng/ μ L. The preferably every mm of reagent composition²Working electrode area contains the anionic surface of about 10～350ng and lives Property agent, more preferably contains 30～220ng/mm²Anion surfactant, more preferably contain 40～150ng/mm²Anion surfactant.

Reagent composition is preferably low total salt reagent composition, and it contains than conventional reagent compositions more The buffer salt of low concentration and/or other salt of lower concentration.Preferably, low total salt reagent composition is every mm²Reagent composition surface area contains the buffer salt of at most 9.54nmol, and in amboceptor at most The inorganic nontransition metal salt of 20% (w/w).It is highly preferred that low total every mm of salt reagent composition² Reagent composition surface area contains the buffer salt of at most 6.43nmol, and at most 10% in amboceptor (w/w) inorganic nontransition metal salt.It is highly preferred that low total every mm of salt reagent composition²Reagent set Compound surface area contains the buffer salt of at most 4.77nmol, and at most 5% (w/w) in amboceptor Inorganic nontransition metal salt.

Preferably, low total salt reagent composition every μ L reservoir volume contains the slow of at most 67nmol Rush the inorganic nontransition metal salt of at most 20% (w/w) in salt, and amboceptor.It is highly preferred that low always Salt reagent composition every μ L reservoir volume contains the buffer salt of at most 45nmol, and in amboceptor The inorganic nontransition metal salt of at most 10% (w/w).It is highly preferred that low total salt reagent composition every μ L Reservoir volume contains the buffer salt of at most 34nmol, and the nothing of at most 5% (w/w) in amboceptor Machine nontransition metal salt.

Preferably, low total every mm of salt reagent composition²Working electrode area contains at most 167nmol Buffer salt, and the inorganic nontransition metal salt of at most 20% (w/w) in amboceptor.More preferably the Low total every mm of salt reagent composition²Working electrode area contains the buffer salt of at most 113nmol, and The inorganic nontransition metal salt of at most 10% (w/w) in amboceptor.It is highly preferred that low total salt reagent set The every mm of compound²Working electrode area contains the buffer salt of at most 84nmol, and in amboceptor at most The inorganic nontransition metal salt of 5% (w/w).

The example of reagent composition is listed in the table below 1.These compositionss are disposed in test sensor On working electrode and antielectrode, wherein the average diameter of working electrode is about 0.2mm²～0.5mm², Antielectrode diameter and working electrode diameter ratio are at least 1.2.The reservoir volume of test sensor is About 0.5 μ L.The average diameter of various reagent compositions is about 2.1mm, thus provides about 3.5mm² Average reagent composition surface area.

Table 1-reagent composition

¹(E)-2-(3H-phenothiazine-3-yldeneamino) benzene-1,4-disulfonic acid

* the inorganic nontransition metal salt of 5% (w/w) is contained

* contains the inorganic nontransition metal salt of 20.6% (w/w)

Reagent composition A and B listed in table 1 is low total salt reagent composition.Compositions A and The every mm of B²Reagent composition surface area contains the buffer salt of at most 9.64nmol, and these groups Amboceptor in compound contains the inorganic nontransition metal salt less than 20% (w/w).On the contrary, table 1 arranges Reagent composition C, D and the E gone out is not low total salt reagent composition.Although compositions C, D Mm every with E²Reagent composition surface area contains the buffer salt of at most 9.64nmol, but these Amboceptor in compositions contains the inorganic nontransition metal salt more than 20% (w/w).

The example of low total salt reagent composition is listed in the table below 2.These compositionss are disposed in test and pass On the working electrode of sensor and antielectrode, wherein the average diameter of working electrode is about 0.2mm²～0.5 mm², antielectrode diameter and working electrode diameter ratio are at least 1.2.The reservoir of test sensor Volume is about 0.5 μ L.The average diameter of reagent composition F and G is about 2.3mm, thus provides About 4.2mm²Average reagent composition surface area.The average diameter of reagent composition H-K is about About 2.1mm, thus about 3.5mm is provided²Average reagent composition surface area.

The low total salt reagent composition of table 2-

¹(E)-2-(3H-phenothiazine-3-yldeneamino) benzene-Isosorbide-5-Nitrae-disulfonic acid, containing the inorganic nontransition metal salt of 4% (w/w)

²Geropon TC-42 (sodium methyl cocoyl taurate)

³Phospholan CS131 (polyoxyethylene nonylphenol phosphate ester)

Arrange by the reagent fluid that deposition volume is 0.35 μ L is deposited and is dried in the upper table 1 of formation The reagent composition gone out.For forming reagent fluid the A '-E ' of the reagent composition listed in table 1 It is listed in the table below 3.

The reagent fluid of table 3-reagent composition

¹(E)-2-(3H-phenothiazine-3-yldeneamino) benzene-1,4-disulfonic acid

* the inorganic nontransition metal salt of 5% (w/w) is contained

* contains the inorganic nontransition metal salt of 20.6% (w/w)

Arrange by the reagent fluid that deposition volume is 0.34 μ L is deposited and is dried in the upper table 2 of formation Reagent composition F and G gone out.By the reagent fluid that deposition volume is 0.2 μ L is deposited and does The reagent composition H-K listed in table 2 in dry formation.For forming the reagent set listed in table 1 The reagent fluid of compound is listed in the table below 4.

The reagent fluid of table 4-reagent composition

²Geropon TC-42 (sodium methyl cocoyl taurate)

³Phospholan CS131 (polyoxyethylene nonylphenol phosphate ester)

Mixed adhesive, buffer salt, amboceptor, surfactant and the preparation of enzyme system can be passed through preferably Reagent fluid.Preferably examination can also be prepared by not comprising one or both of amboceptor and enzyme system Agent fluid.It is then possible to addition water, to form the mixture with desired stability.Examination Agent fluid can contain less kind or extra composition.

Reagent fluid preferably comprises from about 0.1～the binding agent of 1% (w/w), more preferably from about 0.2～0.8% (w/w).At present, particularly preferred reagent fluid contains about 0.3～the binding agent of 0.6% (w/w).As The most optional porous particle is present in reagent fluid, then porous particle suspension and polymeric material Ratio between material is maintained at about 1:10 (w/w).Other ratios can be used for providing not for reagent fluid Same viscosity.The example of the porous particle of reagent fluid is disclosed in such as U.S. Patent Application Publication In 2009/0178936.

Reagent composition preferably comprises the buffer salt keeping the pH value of mixture to be about 4.5～7.5, more Preferably from about 6～7.Can be with the preferable ph of selective reagent fluid and buffer agent to keep the activity of enzyme. The concentration of the buffer salt being incorporated in reagent fluid can be about 30～115 mMs (mM).Preferably Ground, the concentration of the buffer salt being incorporated in reagent fluid is about 40～100mM, more preferably from about 25～75 MM, more preferably from about 30～60mM, more preferably up to 50mM.Can use and there is other concentration Buffer solution.

Reagent fluid can be containing the single or double electron mediator being substantially dissolved in water.Jie in reagent fluid The concentration of body can be about 25～90mM.Preferably, the buffer salt being incorporated in reagent fluid dense Degree is about 30～60mM, more preferably from about 35～40mM.Preferably, the inorganic non-transition in amboceptor The amount of slaine is at most 20% (w/w).It is highly preferred that inorganic nontransition metal salt in amboceptor Amount is at most 15% (w/w), at most 10% (w/w), at most 5% (w/w) and at most 4% (w/w).

Reagent fluid can also contain the enzyme system being substantially dissolved in water, and it has according to manufacturer's regulation The unit of every microlitre (μ L) reagent fluid about 1 active unit to every μ L reagent fluid about 4 active unit Activity, more preferably every μ L reagent fluid about 1.5 active unit is to every μ L reagent fluid about 2 activity The units activity of unit.Owing to the solid weight of the enzyme needed for providing specific unit activity substantially can Because preparation batch and manufacturer change, thus manufacturer is provided for the specified weight of dry enzyme fluid Units activity be preferably used to measure addition.

Reagent fluid preferably comprises from about 0.05～the nonionic surfactant of 0.7% (w/w), more preferably About 0.07～0.5% (w/w).At present, about 0.1～the surfactant of 0.3% (w/w) be particularly preferred 's.Surfactant can contribute to be formed to be had the glue of desired viscosity and stability and hangs Supernatant liquid and any surfactant compatible with deposition process and analysis.Reagent fluid optionally contains Have about 0.005～the anion surfactant of 0.03% (w/w), more preferably from about 0.01～0.02% (w/w)。

Fig. 3 represents for measuring the existence of analyte in the sample contacted with low total salt reagent composition And/or the electrochemical analysis method 300 of concentration.In 310, introduce the sample into containing low total salt The biosensor of reagent composition.In 320, bio-sensor system can recognize that in response to light In material or biologicfluid sample, oxidation/reduction (oxidoreduction) reaction of analyte produces output letter Number.In 330, bio-sensor system measures output signal.In 340, determine in response to At least one Δ S value of at least one error parameter.In 350, from including that at least one is with reference to phase The compensation equation of closing property and at least one Δ S value measures analyte concentration.In 360, concentration is permissible Shown, storage etc..

In 310, introduce the sample into the Sensor section of biosensor, such as, test sensor. Test sensor includes at least one working electrode and at least one antielectrode.Each electrode can contain One or more reagent compositions, at least one of which reagent composition is low total salt reagent fluid. Identical reagent composition can be used on working electrode and antielectrode, or different agent combination Thing can be used to make the operation facility of electrode.Such as, the reagent composition on working electrode can have Help the reaction of analyte, such as enzyme system and amboceptor, and reagent composition on a counter electrode is permissible Contribute to electronics free-flowing between sample and electrode surface, such as reducing substances.

Present in sample, a part of analyte is aoxidized or reduces by chemistry or biochemistry, such as quilt Oxidoreduction oxydasis or reduction.Make the reagent hydration in low total salt reagent composition along with sample and This thing happens.Oxidized or reduction, electronics optionally can turn between analyte and amboceptor Move.Thus, such as from analyte or amboceptor form ionization can measurement of species.

In 320, bio-sensor system is in response to the oxidation of analyte in biologicfluid sample/also Former (oxidoreduction) reaction produces output signal.Electrochemical sensor system can be used to produce output letter Number.Can measurement of species can be charged analyte or charged amboceptor, it be transfused to signal Electrochemistry excitation (being easily oxidized or reduced).Input signal can be set sequence produces pulsation or The signal of telecommunication of break-make, such as electric current or current potential.Input signal is the driving pulse being spaced by relaxation Sequence.In current impulse, during excitation apply current potential within the whole persistent period preferably with base Voltage constant in basis and polarity apply.It is directly compared with some conventional excitation, in routine During the data record of excitation, change in voltage or " scanning " are through multiple voltage potentials and/or polarity.

Input signal can have one or more pulse spacing.Pulse spacing is to constitute cycle of operation Pulse and the summation of relaxation.Each pulse has amplitude and width.The amplitude instruction signal of telecommunication The intensity of current potential or electric current etc..Amplitude can change or substantially constant, such as during amperometry Or during pulse.Pulse width is the persistent period of pulse.Pulse width in input signal can With change or essentially identical.Each relaxation has the persistent period of relaxation width, i.e. relaxation.Defeated The relaxation width entered in signal can change or essentially identical.

By adjusting the excitation of cycle of operation and the width of relaxation, gate input signal can improve point The accuracy of analysis and/or degree of accuracy.Preferably input signal is included in less than 2, during 3 or 5 seconds At least 2,3,4 or 8 cycle of operation applied.It is highly preferred that applied at least 2 in 3 seconds Individual cycle of operation.Preferably, the width of each driving pulse was independently selected from 0.1～2 second, more excellent Choosing was independently selected from 0.2～1 second.At present, particularly preferred input signal pulse width is selected independently From 0.3～0.8 second.The preferably pulse spacing is less than 3, in the range of 2.5 or 1.5 seconds.At present, Pulse width is 0.3～0.5 second and input signal that the pulse spacing is 0.7～2 second is particularly preferred. Input signal can have other pulse widths and interval.

Biosensor can be in response to measurement of species and input signal producing output signal.Output Signal, the most one or more current values, can given either continuously or intermittently measure, and can conduct The function of time is recorded.The output signal being suitable for can comprise up to the signal of stable state and instantaneous Signal.Steady-state current value is observed, such as ± 10 when curent change substantially constant in time Or change within ± 5%.Instantaneous current value is decayed in time.

Preferably, sample experience relaxation.Measurement apparatus can open circuit by test sensor, Hence allow to relaxation.During relaxation, the electric current existed during encouraging substantially is reduced at least one Half, preferably reduce an order of magnitude, more preferably reduce to zero.Preferably, zero current condition is by opening a way Or additive method well known by persons skilled in the art reaches, to provide substantially zero current flowing. Preferably, during relaxation, output signal is not recorded.

Preferably, pulse was executed within the desired time by biosensor continuously from input signal Add to working electrode and antielectrode.Can repeat to include the cycle of operation of excitation and relaxation, or can To apply the cycle of operation with different pulse width and/or interval.

In 330, bio-sensor system is measured defeated in response to be applied on sample by analyte The output signal entering signal and produce, as being produced from the redox reaction of analyte.This system can Given either continuously or intermittently to measure output signal.Such as, bio-sensor system can be in each pulse Period measures output signal off and on, thus obtains multiple current value during each pulse.This is System can show output signal over the display and/or can store output signal in the storage device Or a part for output signal.

In the 340 of Fig. 3, measure the one or more Δ S in response to one or more error parameters Value.Δ S value can be measured for temperature, hematocrit and other contribution factors.

In 350, from including that at least one is with reference to dependency and the compensation equation of at least one Δ S value The analyte concentration of measuring samples.By the analyte concentration by one or more current values Yu sample It is associated, biosensor Optimization Analysis output signal current value.Preferably, from excitation record with The output current value that the analyte concentration of sample is relevant, in this excitation, initial current value is more than decay Introduce the sample into the current value to less than about 7 seconds of test sensor afterwards and in 310. Obtain and sample to less than about 7 seconds of test sensor it is highly preferred that introduce the sample in 310 The output current value that the analyte concentration of product is relevant, and this output current value is from excitation record First current value, in this excitation, the current value after the first current value reduces.Even more preferably, Introduce the sample in 310 and obtain the analyte with sample to less than about 7 seconds of test sensor Concentration dependent output current value, this output current value is the first current value from excitation record, In this excitation, the current value after the first current value reduces, and in the maximum power of test sensor This output current value is obtained during learning performance.Can also analyze extra electric current, the time and/or other Value.In 360, analyte concentration value can be shown, store to be for future reference and/or for Other calculate.

It is 400mg/dL that Fig. 4 illustrates for concentration of glucose and hematocrit is the whole blood of 70% Sample carrys out the output signal of self-test sensor.By measurement apparatus input to the letter testing sensor Number being the gating current pulse trains including 8 excitations by 7 relaxation intervals, the such as U.S. is special Described in profit Shen Qing Publication 2008/0173552.The persistent period of the 2nd to the 8th excitation is equal Being about 0.4 second, the persistent period of the 2nd to the 7th relaxation is all about 1 second.At the 2nd extremely 3 output current values are all recorded during 8th excitation.

Analyze by drawing for the known analyte concentration of a series of stock solutions containing analyte The output electric current of middle particular moment, can prepare the analysis of one or more output current value and sample The dependency of substrate concentration.Dense from the output current value of input signal and the analyte of sample for correction Degree, carrys out the current value after the preferably greater than decay of self-energizing initial current value.Preferably, with sample The relevant output current value of analyte concentration from including reflection test sensor maximum power performance Current data decay obtain.Produce the kinetics of redox reaction of output electric current by multiple The impact of factor.These factors can include speed, enzyme system and the analysis that reagent composition is rehydrated The speed of thing reaction, the speed of enzyme system transfer electronics to amboceptor and amboceptor transfer electronics are to electrode Speed.

During the excitation of gating current pulse train, when having at the beginning of the excitation of decay current value When beginning current value is maximum for multiple excitations, can reach to test the maximum power of sensor Performance.Preferably, when for have decay current value encourage obtain electric current final value be for many During the maximum current final value that individual excitation obtains, reach to test the maximum power performance of sensor.More Preferably, it is maximum when there is the initial current value of excitation of decay current value for multiple excitations And the electric current final value obtained for same excitation is the maximum current final value obtained for multiple excitations Time, reach to test the maximum power performance of sensor.

Maximum power performance can describe with parameter " time to peak ", and this is containing analyte Sample contact electrochemical test sensor after test sensor obtain maximum output current value time Between.Maximum output current value is preferred for the dependency of the analyte concentration with sample.Preferably, The time to peak of test sensor less than from introducing the sample into start about 7 seconds of test sensor, More preferably less than about 5 seconds.Preferably, time to peak is the pact introduced the sample into test sensor In 0.4～7 second, in more preferably from about 0.6～6.4 second, in more preferably from about 1～5 second, more preferably from about 1.1～3.5 In second.In the diagram, reach maximum power performance the analysis time of 3.5 seconds, by " during peak value Between " indicate and show, identify the maximum current value of excitation for all records.

Fig. 5 A and Fig. 5 B illustrate have low total salt reagent composition (A and B) test sensor and When there is the peak value of test sensor of the reagent composition (C, D and E) not being low total salt composite Between scheme.In fig. 5, the concentration of glucose in sample is 50mg/dL.In figure 5b, sample In concentration of glucose be 100mg/dL.The hematocrit of sample is 20%～70%.Each figure The time to peak that the reagent composition A-E listed in table 1 below changes with hematocrit is shown.Right In every kind of compositions, hematocrit is the peak of 20%, 30%, 40%, 50%, 60% and 70% The value time illustrates from left to right.

From Fig. 5 A and the result of Fig. 5 B, the lower content of inorganic nontransition metal salt in amboceptor Relevant to shorter time to peak with relatively low buffer salinity.For having higher hematocrit Sample for, this effect is especially apparent.Thus, low total salt reagent composition is at bio-sensing Device analysis can provide desired time to peak, even if there is of a relatively high hemocyte at sample In the case of specific volume.

The dependency of the analyte concentration of one or more output current values and sample can be adjusted with Compensate the error in measuring.A kind of technology correcting the error relevant with biosensor analysis is to make Use is adjusted with the index function (index function) extracted from the intermediate current value of output current value Dependency in the analyte concentration determined from output current value in sample.Index function is for being used for Determine that from output current value the dependency of analyte concentration can with one or more Compensation Analysis by mistake Difference, and error may result in the deviation of the analyte concentration determined.Index function is corresponding to because dividing One or more errors in analysis and the dependency between analyte concentration and output current value is made Deviation % become.

Deviation % of dependency can be by the one or more Δ S obtained from one or more error parameters Value represents.Δ S value represents the analyte concentration and output signal determined from one or more error parameters Between the slope deviation of dependency.Index function corresponding to slope or slope variation can be by specification Change, with reduce output current value change Statistical Effect, improve output current value change difference, The measurement of normalization output current value and combinations thereof etc..Adjusted dependency can be used for Measure the analyte concentration biological sample from output current value, and with conventional biosensor phase Than accuracy and/or the degree of accuracy with raising.The error correction making index of reference function and Δ S value is recorded Such as in the entitled " slope-based compensation (Slope-based of December in 2008 submission on the 6th Compensation) in international patent application No.PCT/US08/85768 ", inventor Huan-Ping Wu。

Therefore, it is possible to use the index function representing Δ S/S to will be responsive to the defeated of sample concentration of glucose Go out current value and be converted into the calibrated concentration of glucose of sample.Selectively, it is possible to use index Function and equation such as G_corr=G_raw/ (1+f (Index)) from uncorrected glucose concentration value determine through The glucose concentration value of correction, wherein G_corrIt is the calibrated concentration of glucose of sample, G_rawIt is The analyte concentration of the sample determined in the case of not compensating, and f (Index) be index function.

Index function can include the ratio extracted from output signal, exports letter as shown in Figure 4 Number.For example, it is possible to each output signal value is made comparisons in a pulse-signal attenuation circulation, as Ratio R 3=i_3,3/i_3,1, wherein i_3,3Refer to the 3rd current value for the 3rd signal attenuation record, and i_3,1Refer to the first current value for the 3rd signal attenuation record.In another example, Ke Yi Each output signal value is made comparisons, such as ratio in the pulse separated-signal attenuation circulation R4/3=i_4,3/i_3,3, wherein i_4,3Refer to the 3rd current value for the 4th signal attenuation record.Index letter Number can include the combination of the ratio extracted from output signal.In one example, index function can To include the letter ratio of ratio, such as Ratio3/2=R3/R2.In another example, index function can To include the more complicated combination of simpler index function.Such as, index function Index-1 can be with table It is shown as Index-1=R4/3-Ratio3/2.In another example, index function Index-2 can be with table It is shown as Index-2=(R4/3)^p-(Ratio3/2)^q, wherein p and q is positive number independently.

Preferably, the error that index function correction is relevant to hematocrit change.By using energy The test sensor of enough output signals produced with hematocrit change can accelerate this index letter The calculating of number.It is surprising that the test sensor with low total salt reagent composition can carry For this output signal.

Fig. 6 A-6E illustrates Δ S_totalThe dependency graph changed than index R4/3 with letter.These dependencys The glucose output current signal of capillary blood samples that is obtained from 21.8 DEG C of data.Figure The reagent composition of the test sensor of 6A-6E is compositions A-E of table 1 respectively.Have low always The test sensor of salt reagent composition B has optimal value under different hematocrit levels and divides From.

Table 5 list the data for generating Fig. 6 A-6E diagram and at 17.8 DEG C collect similar The R of the different ratios index function of data²Value.R²Value represents the Δ S caused by hematocrit_total And the overall relevance between index.

Table 5-Δ S_totalR with the dependency of ratio index function²Value.

* from the compositions of table 1.

For the output time of less than 5 seconds at 21.8 DEG C, there is low total salt reagent composition (group Compound B) test sensor provide have than provided by other test sensors substantially more preferably R²The dependency of value.For the output time of more than 6.4 seconds at 21.8 DEG C, there is low total salt The test sensor of reagent composition (compositions A) provides to have tests sensor institute than by other The most more preferably R provided²The dependency of value.

For the output time of less than 6.4 seconds at 17.8 DEG C, there is low total salt reagent composition (compositions B) test sensor provide have than by other test sensors provided obvious More preferably R²The dependency of value.For the output time of more than 7.8 seconds at 17.8 DEG C, have low The test sensor of total salt reagent composition (compositions A) provides has ratio by other test sensings The most more preferably R that device is provided²The dependency of value.Thus, under lower analysis temperature, have The test sensor of low total salt reagent composition can not be the reagent of low total salt composite than having More preferable dependency is provided under the test sensor chemical examination time earlier of compositions.

Index function from Fig. 6 A-6E diagram is used for writing relationship equation, has with correction The biosensor analysis deviation of the sample of different hematocrits.Use relevant with Δ S or Multiple index functions can reduce the deviation latitude of emulsion, and the deviation latitude of emulsion is defined makees deviation/deviation universe % Standard deviation.ΔS_totalAnd the dependency between one or more index function to directly influence deviation complete The reduction of the standard deviation (SD) in territory.Therefore, R²Being worth the biggest, the reduction of SD value is the biggest, thus, The deviation latitude of emulsion is the least.Experimental relationship is listed in table 6, wherein for the reagent composition listed in table 1, Be set in before and after listing compensation ± 10/ ± 10% deviation limits in data universe %.Compensating equation quilt Before and after being applied to result, sense for having the test of low total salt reagent composition Device, % ± 10% is significantly larger.

The accuracy of the dependency of table 6-output and analyte concentration.

* from the compositions of table 1.

The improvement that less salt reagent composition provides is it will be evident that fall because of little analysis Outside ± 10/ ± 10% accuracy boundary.By the analysis quantity outside minimizing boundary, obtained more Many readings can be used for the accurate treatment of patient.The calcellation analysis for patient and repetition can also be reduced The needs analyzed.

Fig. 7 illustrates that the test sensor with the reagent composition A-E listed in table 1 is at 21.8 DEG C Under R²It is worth the diagram with the change of chemical examination time.3.5 seconds, 5 seconds, 6.5 seconds, 7.8 seconds and 9.2 seconds The chemical examination time correspond respectively to ratio index function R3/2, R4/3, R5/4, R6/7 and R7/6. Thus, Fig. 7 be table 5 the first half listed by the diagram of result.During for two chemical examinations the earliest Between (3.5 seconds and 5 seconds), low total salt reagent composition B provide at least 0.5 R²Value, and other examinations Agent compositions provides the R of only less than 0.12²Value.For the chemical examination time of 6.5 seconds, low total salt reagent Compositions A and B are provided which the R of at least 0.5²Value, and other reagent compositions provide only 0.2-0.4 R²Value.For the chemical examination time more than 7 seconds, low total salt reagent composition A provides at least 0.5 R²Value；Then, low total salt reagent composition B provides the R less than 0.5²Value.For 7.8 Hes The chemical examination time of 9.2 seconds, the R that reagent composition C-E is provided²It is worth phase reverse with buffer salinity Close.

As shown in the diagram of Fig. 7, low total salt reagent composition can be index function provide corresponding to The R of at least the 0.5 of at most 6.5 seconds chemical examination time²Value.Thus, low total salt reagent composition is permissible Standard is provided for the analyte in sample under the shorter chemical examination time provided than conventional reagent compositions Really analyze.

Fig. 8 illustrates low total salt reagent composition F and G listed in table 2 R5/4 at 16 DEG C Index the diagram with hematocrit levels change.These compositionss are similar, except compositions G is same Shi Hanyou nonionic surfactant and anion surfactant, and compositions F contain only non-from Sub-surface activating agent.The R of result provided for compositions G²Value is 0.82, and for compositions The R of the provided result of F²Value is only 0.32.Thus, existing for of a small amount of anion surfactant The R5/4 index function of this system provides and significantly improves.

Reagent composition B is arranged on the working electrode of test sensor with different-thickness.Table 7 arranges Go out the concentration of amboceptor on each working electrode of four kinds of dissimilar working electrodes.Due to identical Less salt reagent composition reagent composition on each electrode, the most more low concentration and electrode The least thickness be correlated with.The enzyme concentration of every kind of reagent composition is 1.21～1.50 units/square millimeter (U/mm²).Table 7 is also listed and is set in ± 10/ ± 10% deviation for the analysis carried out at different temperatures Data universe % in limit.The working electrode with thin layer less salt reagent composition exists There is in ± 10/ ± 10% deviation limits highest measurement percentage ratio.At lower temperature such as 11 DEG C, this Plant improvement to be especially apparent.

Table 7-is for having the accuracy of the dependency of the less salt reagent layer of different-thickness

Fig. 9 illustrates that the analyte utilizing gating current input signal to measure in the sample of biofluid is dense The schematic diagram of the biosensor 900 of degree.Biosensor 900 includes can be at any analyser The measurement apparatus 902 implemented in device and test sensor 904, including desktop apparatus, portable or hands Held device etc..Biosensor 900 can be used to measure analyte concentration, including glucose, The concentration of uric acid, lactate, cholesterol, bilirubin etc..Although showing biosensor 900 Particular configuration, but it can have other structure, including the structure with additional components.

Test sensor 904 has formation reservoir 908 and the passage 910 with opening 912 Base portion 906.Reservoir 908 and passage 910 can be covered by the lid with vent.Reservoir 908 define partially enclosed volume.Reservoir 908 can be containing the group assisting in keeping fluid sample Point, such as water-swelling polymer or porous polymer substrate.Can be by reagent deposition in reservoir 908 and/or passage 910 in.Reagent composition at working electrode 904 contains low total salt reagent set Compound and can be containing the material such as one or more enzyme system, amboceptors.Can use identical or different Reagent composition formed antielectrode 905, be preferably used lack enzyme system reagent composition.Test passes Sensor 904 can also have the sample interface 914 that neighbouring reservoir 908 is arranged.Sample interface 914 Reservoir 908 can be surrounded partially or completely.Test sensor 904 can have other structures.

Sample interface 914 has the conductor 909 being connected with working electrode 904 and antielectrode 905. Each electrode can be the most at grade or in more than one plane.Electrode 904,905 Can be arranged on the surface of the base portion 906 forming reservoir 908.Electrode 904,905 can prolong Stretch or be projected in reservoir 908.Dielectric layer can partly cover conductor 909 and/or electrode 904、905.Sample interface 914 can have other electrodes and conductor.

Measurement apparatus 902 includes the circuit being connected with sensor interface 918 and display 920 916.Circuit 916 includes being situated between with signal generator 924, optional temperature sensor 926 and storage The processor 922 that matter 928 is connected.

Electrical input signal is supplied to sensor interface in response to processor 922 by signal generator 924 918.Electrical input signal can be transmitted to sample interface 914 by sensor interface 918, so that electricity is defeated Enter signal and be applied to the sample of biofluid.Electrical input signal can be current potential or electric current, and can Apply with multiple-pulse, sequence or endless form.Signal generator 924 can also be as generator-note Record device record is from the output signal of sensor interface.

The sample in the reservoir being in test sensor 904 is measured in optional temperature sensor 926 Temperature.The temperature of sample can be measured, can calculate from output signal, or supposes and ring The temperature of the device of border temperature or enforcement bio-sensor system is same or similar.Temperature-sensitive can be used Ohm gauge, thermometer or other temperature-sensing devices measure temperature.Other technologies can be used to survey Amount sample temperature.

Storage medium 928 can be magnetic memory, optical memory or semiconductor memory, other Storage device etc..Storage medium 928 can be that fixed-storage device, such as storage card etc. are removable Storage device or remote access storage device etc..

Processor 922 utilizes the computer readable software code sum being stored in storage medium 928 According to implementing analyte analyzation and data process.Processor 922 can be in response to sensor interface 918 Place tests the existence of sensor 904, is applied to sample test on sensor 904, in response to making The input of user etc. and start the analysis of analyte.Processor 922 pointing signal generator 924 to Sensor interface 918 provides electrical input signal.Processor 922 can be from optional temperature sensor 926 receive sample temperature.Processor 922 receives output signal from sensor interface 918.This output Signal is in response to the redox reaction of the analyte in reservoir 908 and produces.

Preferably, output signal measured by processor 922, to obtain current value from excitation, swashs at this Encourage after initial current value is more than decay and introducing the sample into testing the little of sensor 904 Current value in about 3 seconds.It is highly preferred that output signal measured by processor 922, with by sample Product are introduced to test the less than about acquisition current value in 3 seconds of sensor 904, and this processor obtains Must be from the first current value of excitation record, in this excitation, the current value after the first current value is continuous Reduce.Even more preferably, output signal measured by processor 922, to introduce the sample into test The less than about acquisition current value in 3 seconds of sensor 904, it is thus achieved that from the first current value of excitation record, In this excitation, the current value after the first current value is continuously reduced, and at test sensor Current value is obtained during big dynamic performance.

Utilize the one or more relationship equation in processor 922 can be by one or more acquisitions Current value be associated with the analyte concentration of sample.The result of analyte analyzation can be output to Display 920 also can be stored in storage medium 928.Preferably, the result of analyte analyzation It is output to display 920, more to test 5 seconds of sensor or in less time introducing the sample into Preferably, result can introduce the sample into test 3 seconds of sensor or in less time defeated Go out to display 920.

Can to graphically, mathematical way, a combination thereof mode etc. represent relate to analyte concentration and The relationship equation of output current value.Can be by the program number being stored in storage medium 928 Distribution (PNA) table, another kind of inquiry table etc. represent relationship equation.Can be situated between by being stored in storage Computer readable software code in matter 928 provides the instruction relevant with the enforcement of analyte analyzation. Code can be object code or description or any other code controlling function described herein.Can The data from analyte analyzation are carried out one or more data process in processor 922, Including measuring rate of decay, K constant and ratio etc..

Sensor interface 918 has and the conductor 909 in the sample interface 914 of test sensor 904 Connect or the contact point of electric connection.Sensor interface 918 by electrical input signal from signal generator 924 By the conductor 909 in contact point transmission to sample interface 914.Sensor interface 918 also will output Signal is transmitted to processor 922 and/or signal generator 924 by contact point from sample.

Display 920 can be analogue type or numeric type.This display can be to be suitable for display number The LCD of value reading.

In use, by sample for analysis is introduced opening 912, sample is transferred to reservoir In 908.Sample flows through passage 910, inserts in reservoir 908, discharges the sky previously contained simultaneously Gas.Sample and the reagent generation chemical reaction being deposited in passage 910 and/or reservoir 908.Excellent Selection of land, sample is fluid, it is highly preferred that be liquid.

Test sensor 902 is neighbouring with measurement apparatus 902 to be arranged.Close position includes sample interface 914 with the position of sensor interface 918 electric connection.Electric connection includes that input and/or output signal exist Wired between contact point in sensor interface 918 and the conductor 909 in sample interface 914 or It is wirelessly transferred.

Although it have been described that various embodiments of the present invention, but those skilled in the art are obvious Other embodiments and embodiment can be made within the scope of the invention.

Claims

1. for measuring a test sensor for the analyte concentration in sample, comprising:

At least two conductor, one of them conductor is working electrode；With

Being arranged in the reagent composition on described working electrode or near it, described reagent composition has There is average reagent composition surface area and contain:

Binding agent,

Concentration is every mm²The buffer salt of described reagent composition surface area at most 9.54nmol,

Concentration is every mm²The amboceptor of described reagent composition surface area at most 4.76nmol, its Described in amboceptor contain the inorganic nontransition metal salt of at most 20% (w/w),

Enzyme system,

Nonionic surfactant, and

Ionic surface active agent.

2. sensor as claimed in claim 1, wherein said ionic surface active agent include cloudy from Sub-surface activating agent.

3. sensor as claimed in claim 2, wherein said reagent composition contains every mm² Described reagent composition surface area about 3～the anion surfactant of 16ng.

4. sensor as claimed in claim 1, wherein said reagent composition contains:

Every mm²The described binding agent of described reagent composition surface area about 0.14～0.43 μ g,

Every mm²The described buffer salt of described reagent composition surface area about 2.30～9.54nmol,

Every mm²The described amboceptor of described reagent composition surface area about 1.70～4.76nmol,

Every mm²The described enzyme system of described reagent composition surface area about 0.07～0.3 unit, and

Every mm²The described non-ionic surface of described reagent composition surface area about 0.04～0.24 μ g is lived Property agent.

5. sensor as claimed in claim 4, wherein said reagent composition contains:

About 3.40～4.77nmol/mm²Described buffer salt；With

About 2.80～4.00nmol/mm²Described amboceptor.

6. for measuring a test sensor for the analyte concentration in sample, comprising:

There is the reservoir of reservoir volume；

At least two conductor in described reservoir, one of them conductor is working electrode；With

It is arranged in the reagent composition on described working electrode or near it,

Wherein said reagent composition contains:

Binding agent,

Concentration is the buffer salt of reservoir volume at most 67nmol described in every μ L,

Concentration is the amboceptor of reservoir volume at most 40nmol, wherein said Jie described in every μ L Body contains the inorganic nontransition metal salt of at most 20% (w/w),

Enzyme system,

Nonionic surfactant, and

Ionic surface active agent.

7. sensor as claimed in claim 6, wherein said ionic surface active agent include cloudy from Sub-surface activating agent.

8. sensor as claimed in claim 6, wherein said reagent composition contains every μ L institute State reservoir volume about 20～the ionic surface active agent of 40ng.

9. sensor as claimed in claim 6, wherein said reagent composition contains:

The described polymer adhesive of reservoir volume about 1～3 μ g described in every μ L,

The described buffer salt of reservoir volume about 16～67nmol described in every μ L,

The described amboceptor of reservoir volume about 12～40nmol described in every μ L,

The described enzyme system of reservoir volume about 0.5～1.8 unit described in every μ L, and

The described nonionic surfactant of reservoir volume about 0.3～1.7 μ g described in every μ L.

10. sensor as claimed in claim 9, wherein said reagent composition contains:

The described buffer salt of about 24～34nmol/ μ L, and

The described amboceptor of about 20～28nmol/ μ L.

11. 1 kinds of test sensors being used for measuring the analyte concentration in sample, comprising:

At least two conductor, one of them conductor is the working electrode with working electrode area；With

Being arranged in the reagent composition on described working electrode or near it, described reagent composition contains Have:

Binding agent,

Concentration is every mm²The buffer salt of described working electrode area at most 167nmol,

Concentration is every mm²The amboceptor of described working electrode area at most 100nmol, Qi Zhongsuo Give an account of the inorganic nontransition metal salt that body contains at most 20% (w/w),

Enzyme system,

Nonionic surfactant, and

Ionic surface active agent.

12. sensors as claimed in claim 11, wherein said ionic surface active agent includes the moon Ionic surface active agent.

13. sensors as claimed in claim 11, wherein said reagent composition contains every mm² Described working electrode area about 10～the ionic surface active agent of 350ng.

14. sensors as claimed in claim 11, wherein said nonionic surfactant includes Sugar surfactants.

15. sensors as claimed in claim 11, wherein said reagent composition contains:

Every mm²The described binding agent of described working electrode area about 1～7.5 μ g,

Every mm²The described buffer salt of described working electrode area about 16～167nmol,

Every mm²The described amboceptor of described working electrode area about 12～100nmol,

Every mm²The described enzyme system of described working electrode area about 0.5～5 unit, and

Every mm²The described nonionic surfactant of described working electrode area about 0.3～4.3 μ g.

16. sensors as claimed in claim 11, wherein said reagent composition contains:

Every mm²Described working electrode area about 24～84nmol/mm²Described buffer salt, and

Every mm²Described working electrode area about 20～70nmol/mm²Described amboceptor.

17. sensors as claimed in claim 11, wherein said buffer salt includes Na₂HPO₄。

18. sensors as claimed in claim 11, wherein said amboceptor contains at most 5% (w/w) Inorganic nontransition metal salt.