CN100437110C

CN100437110C - Pretreatment method for liquid-phase micro-extraction sample

Info

Publication number: CN100437110C
Application number: CNB2007100516049A
Authority: CN
Inventors: 徐晖; 潘文慧; 任贻军
Original assignee: Huazhong Normal University
Current assignee: Huazhong Normal University
Priority date: 2007-03-02
Filing date: 2007-03-02
Publication date: 2008-11-26
Anticipated expiration: 2027-03-02
Also published as: CN101017160A

Abstract

This invention relates to one liquid phase extract sample front process method, which comprises the following steps: a, taking one magnetic mixture device and one tube cover PCR tube for 0.2 ml without cover, one sample bottle, bottle plug and mixture magnetic probe; b, containing extraction liquid in bottom of PCR tube for liquid sealing by sample liquid; c, plugging the PCR tube into bottle plug; d, taking sample liquid in the sample bottle with mixture magnetic probes; e, containing the plug of tube into sample bottle for mixing and extraction.

Description

A kind of pretreatment method for liquid-phase micro-extraction sample

Technical field

The present invention relates to pretreatment method for liquid-phase micro-extraction sample.

Background technology

The sample pre-treatments technology has material impact to analysis result, receives much attention always.The preconditioning technique of widespread use at present has liquid-liquid extraction (LLE), Solid-Phase Extraction (SPE), solid-phase microextraction (SPME), membrane extraction etc.Classical liquid-liquid extraction complex operation uses a large amount of organic solvents poisonous or harmful to human and environment, and is difficult for realizing robotization.Advantages such as the SPE technology is with efficiently, and is reliable, and solvent load is few are rapidly developed in a lot of fields, but it needs wash-out, and purifying substance is to satisfy the requirement of gas chromatography (GC) or high performance liquid chromatography instrumental analysis such as (HPLC).SPME is a kind of solvent-free sample pre-treatments technology, the centralized procurement sample, and extraction concentrates in one, has advantages such as simple, quick, convenient, at environmental sample, food and widespread use clinically.But the SPME extracting head is more expensive, and serviceable life is short, repeatedly uses also there is cross-contamination issue special desorption apparatus of need also during with the HPLC coupling with it.Liquid-phase micro-extraction (LPME) is grow up along with the development of environmental analysis in modern age technology quick, and is accurately, highly sensitive, eco-friendly novel pretreatment technology (JeannotM.A, Cantwel1 F.F., Anal Chem, 1996,68:2236-2240.), combine the advantage of LLE and SPME, required organic solvent is few, and is simple to operate, and treasury is got, purifying, concentrate in one the step finish, highly sensitive, concentration effect is good.This technology not only can be used separately, also can with gas chromatography, liquid chromatography coupling.LPME has two kinds of forms: a kind of list drip micro-extraction (single drop microex-traction, SDME)., a kind of be the hollow-fibre membrane liquid-phase micro-extraction (liquidphase microext raction supported by hollow fibermembrane, HF-LPME).

With regard to single dropping liquid-phase microextraction, its concrete operations fill in the sample bottle of testing sample for the micro syringe that will fill a small amount of (2-5 microlitre) extractant inserts, careful pushing syringe piston, make the extractant of storing in the syringe form small drop at needle point, use solution in the magnetic agitation sample bottle, test analyte is constantly entered in the drop from sample solution.This method has been successfully used to measure organic contaminants such as various water samples, the volatility in the samples such as tap water, biological sample, fruit, vegetables, soil, half volatile, involatile, as palycyclic aromatic, phenols, many chlorine aromatic hydrocarbons, aromatic amine, (Vanessa C., Chrystelle B.-M., Lu Y. such as benzene oxygen ether-derivative herbicides and phthalate ester, Paulette M., RalphE.S., Zolt á n M., Talanta, 2004,63:555-560.; Yadollah Y., Mohammad H., Majid H.-H., Mojtaba S., Talanta, 2004,62:265-270.; Lorena V., Antonio C., Nicolas K., ElefteriaP.., Journal of Chromatography A, 2005,1089:25-30.).

Yet in experiment, there is following problem;

(1) because drop relies on the surface tension between liquid and solid to be suspended on the needle point purely, make the extractant volume can not be too big (generally being no more than 5 microlitres), and suitably increase the sensitivity that the extractant volume helps improving extraction efficiency and method.

(2) drop that hangs on the needle point can drip because of small vibrations, thereby experiment is very high to the experimental situation requirement, also need experimental implementation person extremely careful, and the stirring rate of sample cell also must be transferred very lowly.

(3) reducing owing to droplet size, its vapour pressure rises, cause the extractant highly volatile, the extraction time is restricted, in general analyte had just stopped extraction before the balance between the two-phase reaches, balance can not really realize, causes concentration effect relatively poor relatively, and sensitivity is relatively low.

With regard to the hollow-fibre membrane liquid-phase micro-extraction, the hollow-fibre membrane liquid-phase micro-extraction is inserted on the microsyringe syringe needle an other end of diaphragm seal with an end of the hollow-fibre membrane of certain-length (generally being about 1cm) exactly.Before extracting, hollow-fibre membrane is immersed in as in the organic solution that receives the phase extractant, organic solution is fixed among the micropore of hollow-fibre membrane.In HF-LPME, determinand can enter into the syringe of hollow-fibre membrane inside by being fixed on water-fast organic reception phase solvent in the hollow fiber membrane micropore.This sample pre-treatments technology still has problems.

Big problem is:

The stability of liquid film and serviceable life.Because liquid film is fixed on the microporous barrier all the time, the selection of organic solvent is most important to its stability influence in the liquid film, must satisfy conditions such as water-insoluble, non-volatile and low viscosity, so have only a few organic solvent (n-undecane, n-hexyl ether etc.) available, use these separated from solvent enrichment polar compounds, efficient is often lower.

Summary of the invention

The present invention is exactly at above-mentioned deficiency, and conventional liquid-phase microextraction method is improved, and a kind of micro-extracting method for treating liquid phase before analysing samples is provided.

Technical scheme of the present invention is as follows:

A kind of pretreatment method for liquid-phase micro-extraction sample, its operation steps comprises:

1), gets a magnetic stirring apparatus, 0.2 milliliter of PGR pipe having wiped out the pipe lid, a sample bottle, bottle stopper, stirring magneton;

2), at an amount of extract of the bottom of PCR pipe splendid attire, carry out fluid-tight with sample solution again;

3), the PCR mouth of pipe is filled in the bottle stopper of sample bottle up;

4), in sample bottle the splendid attire sample solution, put into the stirring magneton;

5), bottle stopper that described PCR pipe will be housed fills in the sample bottle that fills sample solution, allows the sample bottle side direction be placed on the magnetic stirring apparatus, stir, extract

Wherein said sample bottle is common 8.0 ml penicillin reagent bottles or other vial, joins bottle stopper (rubber plug); The PCR pipe is exactly the tip plastics small tubes of similar centrifuge tube, and its formal name used at school is exactly the PCR pipe.

In the said method, the pipe of 0.2 milliliter of PCR pipe lid is wiped out in advance, and the bottom is loaded with an amount of extractant (the 10-100 microlitre depends on the needs), splashes into sample solution and carries out fluid-tight.The PCR pipe mouth of pipe that extract is housed is filled in the bottle stopper of sample bottle up.Again this bottle stopper is filled in the sample bottle that fills sample solution sealing.The effect of PCR pipe is the splendid attire extractant.Be suspended on the pipe end drop except be subjected to gravity and and the PCR tube wall between the absorption affinity effect, also be subjected to the acting force of fluid-tight liquid to it.Because the combined action of three acting forces, it is bigger that droplet size can reach.Consider the sample size of liquid chromatography, general 20 microlitres of selecting of extractant volume.In the said apparatus, the effect of stirring is to quicken to reach balance time.

The advantage of liquid-phase microextraction method of the present invention

1, replace the micro syringe needle point with the PCR pipe, it is big to store the extractant volume, and stirring rate can strengthen, and can comparatively fast reach balance.

2, the range of choice of the used organic solvent of extraction is extensive, only need satisfy water-insoluble and has certain solubleness to get final product to sample, has enlarged the range of application of method widely.

2, can keep its advantages of higher stability, reappearance in experimentation.

3, the time of extracting can access prolongation effectively to make extraction quantity increase simultaneously greatly; The extraction efficiency height, simple, convenient, cheap, the organic solvent consumption is little.

Operation that this method is greatly easy, can effectively avoid the failure that causes because of carelessness because of the operator in the scientific research, the conventional liquid-phase microextraction method of the sensitivity of this method and extraction efficiency greatly improves simultaneously, is very suitable for extraction, the enrichment of involatile component in the various sample solutions.

Description of drawings:

Fig. 1 is a liquid-phase micro-extraction apparatus structure synoptic diagram of the present invention.

Among the figure: 1, magnetic stirring apparatus, 2,0.2 milliliters of PCR pipe (the pipe lid is wiped out in advance), 3, sample bottle, 4, bottle stopper, 5, stir magneton.

Embodiment

The exemplary construction of the bright liquid-phase microextraction method of we as shown in Figure 1, its device comprises 2, one sample bottles 3 of 1, one 0.2 milliliter of PCR of magnetic stirring apparatus pipe (the pipe lid is wiped out in advance), bottle stopper 4 stirs magneton 5.An amount of extract of bottom splendid attire at PCR pipe 2, carry out fluid-tight with an amount of sample liquid again, the PCR mouth of pipe is filled in up in the bottle stopper 4 of sample bottle 3, in the sample bottle 3 that fills analyte solution (sample solution), put into the stirring magneton, the bottle stopper 4 that described PCR pipe is housed is filled in the sample bottle 3 that fills sample solution, sample bottle 3 side direction are placed on the magnetic stirring apparatus, stir, extract.

Utilize Flumetsulam and two analog in the liquid-phase microextraction method mensuration water sample of the present invention:

With 8 milliliter of 1 mcg/ml sample (Flumetsulam, Flumetsulam analog I, Flumetsulam analog II, solution is for acid) and 0.32 gram NaCl add 8.0 ml penicillin reagent bottles, manage the splendid attire extract with PCR, extracting sample solution carries out fluid-tight, the PCR mouth of pipe is filled in up in the bottle cap of sample bottle, with the bottle cap jam-pack, sealing adds in sample bottle and stirs the magneton stirring.

Chromatographic condition: chromatographic column; The XBPC18 post; Moving phase: methyl alcohol: water=45: 55 (volume ratio adds an amount of phosphoric acid in the water); Flow velocity: 0.8 ml/min; Detect wavelength: 225 nanometers.

Extraction efficiency of the present invention is compared with the extraction efficiency of conventional headspace liquid-phase microextraction, the former be the latter 6-9 doubly.And being applied to the mensuration of Flumetsulam in the actual soil-like and analog thereof, the recovery is between 80.9-96.0%.The minimum detectability of Flumetsulam and analog thereof is respectively 0.8 nanograms/milliliter, 0.5 nanograms/milliliter and 0.5 nanograms/milliliter.In a few days and day to day precision between 3.65%-9.34%.Used PCR pipe, penicillin bottle, magnetic stirring apparatus, stirring magneton in the liquid-phase microextraction method of the present invention, be commercially available thing, and method of operating is simple, easily row, the extraction efficiency height can be applied to extraction, the enrichment of involatile component in the various samples.

Claims

1, a kind of pretreatment method for liquid-phase micro-extraction sample is characterized in that it comprises:

1), gets a magnetic stirring apparatus (1), 0.2 milliliter of PCR pipe (2) of wiping out the pipe lid, a sample bottle (3), bottle stopper (4), stirring magneton (5);

2), at the bottom splendid attire extract of PCR pipe (2), carry out fluid-tight with sample solution again;

3), PCR pipe (2) mouth is filled in the bottle stopper (4) of sample bottle (3) up;

4), in sample bottle (3) the splendid attire sample solution, put into the stirring magneton;

5), bottle stopper (4) that described PCR pipe (2) will be housed fills in the sample bottle (3) that fills sample solution, allows the sample bottle side direction be placed on the magnetic stirring apparatus, stir, extract.

2, pretreatment method for liquid-phase micro-extraction sample according to claim 1 is characterized in that sample bottle (3) is common 8.0 ml penicillin reagent bottles or other vial.