CN107144552A - The method for detecting total arsenic content and total mercury content in dairy products - Google Patents
The method for detecting total arsenic content and total mercury content in dairy products Download PDFInfo
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- CN107144552A CN107144552A CN201710316665.7A CN201710316665A CN107144552A CN 107144552 A CN107144552 A CN 107144552A CN 201710316665 A CN201710316665 A CN 201710316665A CN 107144552 A CN107144552 A CN 107144552A
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- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
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- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
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- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/64—Fluorescence; Phosphorescence
- G01N21/6428—Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes"
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- G01N21/64—Fluorescence; Phosphorescence
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- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
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Abstract
The invention discloses the method for total arsenic content and total mercury content in detection dairy products, method includes:Dairy products to be measured are subjected to micro-wave digestion, to obtain digestion solution;The digestion solution is mixed with sulfamic acid, to obtain neutralizer;The neutralizer is mixed with reducing agent, to obtain prepare liquid;And the prepare liquid is subjected to spectroscopic methodology detection, and the total arsenic content and total mercury content in the dairy products to be measured are determined based on testing result.This method is removed using sulfamic acid to be carried out clearing up the nitric acid used in processing to sample, and reaction is gentle, easy to operate, and testing result has the higher degree of accuracy and precision.
Description
Technical field
The present invention relates to field of food science, specifically, the present invention relates to total arsenic content and total mercury in detection dairy products
The method of content.
Background technology
Arsenic and mercury are common pollution elements in dairy products, and long-term consumption can be made by the dairy products of arsenic and mercury pollution to human body
Into serious harm.
However, the method for total arsenic content and total mercury content still has much room for improvement in existing detection dairy products.
The content of the invention
The present invention is that the discovery of following facts and problem is proposed based on inventor:
In existing detection dairy products in the method for total arsenic content and total mercury content, nitric acid and peroxidating are typically used first
Hydrogen is cleared up to dairy products to be measured, then using the nitric acid in saturation sodium hydroxide solution and in system, however, saturation hydrogen-oxygen
Change sodium and nitric acid reaction is very violent, and produce substantial amounts of heat, serious meeting causes sample splash, influences the standard of testing result
True property;In addition, using saturation sodium hydroxide solution the fluorescence intensity of sample can also increased, cause total arsenic content in testing result
It is higher with total mercury content.
In consideration of it, the method that the present invention proposes total arsenic content and total mercury content in detection dairy products.This method uses ammonia
The removal of base sulfonic acid carries out clearing up the nitric acid used in processing to sample, and reaction is gentle, easy to operate, and testing result is with higher
The degree of accuracy and precision.
In one aspect of the invention, the present invention proposes a kind of side for detecting total arsenic content and total mercury content in dairy products
Method.Embodiments in accordance with the present invention, this method includes:Dairy products to be measured are subjected to micro-wave digestion, to obtain digestion solution;By institute
State digestion solution to mix with sulfamic acid, to obtain neutralizer;The neutralizer is mixed with reducing agent, it is to be measured to obtain
Liquid;And the prepare liquid is subjected to spectroscopic methodology detection, and determine that total arsenic in the dairy products to be measured contains based on testing result
Amount and total mercury content.
Thus, embodiments in accordance with the present invention, this method removes the nitric acid in digestion solution, sulfamic acid using sulfamic acid
The nitrate ion in nitric acid, nitrite ion and volatile nitrogen oxide can be converted into nitrogen well, so that
Reach removal nitric acid purpose, it is to avoid nitric acid and the reducing agent reaction subsequently added make sample discoloration, splash, and sulfamic acid will not
Fluorescence intensity to sample is impacted, so that the degree of accuracy of testing result is improved, meanwhile, sulfamic acid and nitric acid reaction temperature
With, it is simple to operate, it is possible thereby to which it is time-consuming to substantially reduce detection.
In addition, the method for total arsenic content and total mercury content can be with detection dairy products according to the above embodiment of the present invention
With technical characteristic additional as follows:
In some embodiments of the invention, the dairy products to be measured, nitric acid and hydrogen peroxide are mixed in advance, and
Resulting mixed liquor is subjected to the micro-wave digestion, wherein, the dairy products to be measured, the nitric acid and the hydrogen peroxide
Amount ratio is (0.2~2.0g):(4~5mL):2.0mL.Thus, it is possible to significantly improve the degree of accuracy of testing result.
In some embodiments of the invention, the sulfamic acid concentration is 100g/L, based on digestion solution described in 6mL, institute
The consumption for stating sulfamic acid is 2.5mL.Thus, it is possible to effectively remove the nitric acid in the digestion solution, and then further improve
The degree of accuracy of testing result.
In some embodiments of the invention, the neutralizer based on 8.5mL, the consumption of the reducing agent is 2.5mL.By
This, can further improve the degree of accuracy of testing result.
In some embodiments of the invention, it is 50g/L thiourea solution and dense that the reducing agent, which is included selected from concentration,
Spend at least one of 15~20g/L sodium borohydride solution.
In some embodiments of the invention, the prepare liquid is detected using two-channel atomic XRF.
In some embodiments of the invention, the testing conditions of the two-channel atomic XRF include:Arsenic photoelectricity
Multiplier tube negative high voltage:240V;Arsenic lamp current:60mA;Mercury photomultiplier negative high voltage:240V;Mercury lamp electric current:60mA;Atomization
Device height:10.0mm;Flow rate of carrier gas:300mL/min;And shield gas flow speed:800mL/min.Thus, it is possible to further improve
The degree of accuracy of testing result.
The additional aspect and advantage of the present invention will be set forth in part in the description, and will partly become from the following description
Obtain substantially, or recognized by the practice of the present invention.
Brief description of the drawings
The above-mentioned and/or additional aspect and advantage of the present invention will become from description of the accompanying drawings below to embodiment is combined
Substantially and be readily appreciated that, wherein:
Fig. 1 is that the method flow of total arsenic content and total mercury content in detection dairy products according to an embodiment of the invention shows
It is intended to.
Embodiment
Embodiments of the invention are described below in detail.The embodiments described below is exemplary, is only used for explaining this hair
It is bright, and be not considered as limiting the invention.Unreceipted particular technique or condition in embodiment, according to text in the art
Offer described technology or condition or carried out according to product description.Agents useful for same or the unreceipted production firm person of instrument,
For can be by the conventional products of acquisition purchased in market.
In one aspect of the invention, the present invention proposes a kind of side for detecting total arsenic content and total mercury content in dairy products
Method.Embodiments in accordance with the present invention, this method includes:Dairy products to be measured are subjected to micro-wave digestion, to obtain digestion solution;It will disappear
Solution liquid is mixed with sulfamic acid, to obtain neutralizer;Neutralizer is mixed with reducing agent, to obtain prepare liquid;And will
Prepare liquid carries out spectroscopic methodology detection, and determines based on testing result total arsenic content and total mercury content in dairy products to be measured.
The method to total arsenic content and total mercury content in detection dairy products according to embodiments of the present invention is carried out in detail below
Description, with reference to Fig. 1, this method includes:
S100:Micro-wave digestion
In the step, dairy products to be measured are subjected to micro-wave digestion, to obtain digestion solution.Embodiments in accordance with the present invention,
Dairy products to be measured, nitric acid and hydrogen peroxide can be mixed in advance, and resulting mixed liquor is subjected to micro-wave digestion, its
In, the amount ratio of dairy products to be measured, nitric acid and hydrogen peroxide is (0.2~2.0g):(4~5mL):2.0mL, it is possible thereby to significantly
Improve the degree of accuracy of testing result.
Embodiments in accordance with the present invention, inventor has found, if the amount of dairy products to be measured is excessive in mixed liquor, is not only difficult
Clear up, also result in digestion process acutely, sample overflows, and the amount of dairy products to be measured is too small, testing result can be caused to be forbidden
Really, thus, inventor has carried out lot of experiments, and the effect that the addition of dairy products to be measured is 0.2~2.0g is therefrom determined
Preferably.In addition, the addition of nitric acid and hydrogen peroxide depends on the addition of dairy products to be measured, the addition of nitric acid and hydrogen peroxide
Amount is too small, can not fully clear up dairy products to be measured, addition is excessive, can cause sample splash.
The concentration of embodiments in accordance with the present invention, nitric acid and hydrogen peroxide is not particularly restricted, those skilled in the art
Can be selected according to actual needs, according to the specific embodiment of the present invention, the concentration of nitric acid can for 65.0~
68.0wt%, the concentration of hydrogen peroxide can be 30wt%, thus significantly improve the degree of accuracy of testing result.
Embodiments in accordance with the present invention, the operating condition of micro-wave digestion is not particularly restricted, and those skilled in the art can
To be selected according to actual needs.
S200:Remove nitric acid
In the step, digestion solution is mixed with sulfamic acid, to obtain neutralizer.According to the implementation of the present invention
Example, sulfamic acid can be well by the nitrate ion in nitric acid, nitrite ion and volatility conversion of nitrogen oxides
For nitrogen, nitric acid purpose is removed so as to reach, it is to avoid nitric acid and the reducing agent reaction subsequently added make sample discoloration, splash, and
Sulfamic acid will not be impacted to the fluorescence intensity of sample, so that the degree of accuracy of testing result is improved, meanwhile, sulfamic acid sheet
Body non-corrosiveness, and, no exothermic phenomenon gentle with nitric acid reaction, after digestion solution and sulfamic acid mixture are reacted completely,
Without waiting for reaction solution cooling, subsequent step can be directly carried out, so that it is time-consuming to reduce detection.
Embodiments in accordance with the present invention, the concentration of sulfamic acid is not particularly restricted, and those skilled in the art can root
Selected according to being actually needed, according to the specific embodiment of the present invention, sulfamic acid can be the water that concentration is 100g/L
Solution, thus, it is possible to effectively remove the nitric acid in digestion solution, and then further improves the degree of accuracy of testing result.
Embodiments in accordance with the present invention, based on 6mL digestion solutions, the consumption of sulfamic acid can be 2.5mL.It is possible thereby to enter
One step effectively removes the nitric acid in digestion solution, and then further improves the degree of accuracy of testing result.
S300:Mixed with reducing agent
In the step, neutralizer is mixed with reducing agent, to obtain prepare liquid.Specifically, the arsenic in dairy products to be measured
May in a variety of forms exist with mercury, by adding reducing agent, the arsenic in dairy products to be measured and mercury can be reduced, so that
Arsenic hydride and atomic state mercury are obtained, to be detected.
Embodiments in accordance with the present invention, reducing agent can include selected from concentration be 50g/L thiourea solution and concentration be
At least one of 15~20g/L sodium borohydride solution.Embodiments in accordance with the present invention, thiocarbamide can be by dairy products to be measured
Pentavalent arsenic be reduced to trivalent arsenic, and trivalent arsenic further can be converted into arsenic hydride by sodium borohydride, and mercury compound is turned
Atomic state mercury is turned to, to be detected.
Embodiments in accordance with the present invention, the neutralizer based on 8.5mL, the consumption of reducing agent can be 2.5mL, it is possible thereby to
The arsenic and mercury in dairy products to be measured are fully converted into arsenic hydride and atomic state mercury, so as to significantly improve the accurate of testing result
Degree.
S400:Determine testing result
In the step, prepare liquid is subjected to spectroscopic methodology detection, and determines based on testing result total arsenic in dairy products to be measured
Content and total mercury content.
Embodiments in accordance with the present invention, can be detected using two-channel atomic XRF to prepare liquid.Thus,
The fluorescence intensity of arsenic and mercury in prepare liquid can be detected respectively simultaneously.
Embodiments in accordance with the present invention, can before being detected to prepare liquid using two-channel atomic XRF,
The sodium borohydride solution that concentration is 15~20g/L is added into prepare liquid, it is possible thereby to further fully by dairy products to be measured
In arsenic and mercury be converted into arsenic hydride and atomic state mercury so that further improve testing result the degree of accuracy.
According to a particular embodiment of the invention, the prepare liquid based on 1.5mL, the addition of sodium borohydride solution can be
2.5mL, it is possible thereby to the arsenic and mercury in dairy products to be measured fully further are converted into arsenic hydride and atomic state mercury, so as to enter
One step improves the degree of accuracy of testing result.
Embodiments in accordance with the present invention, the testing conditions of two-channel atomic XRF can include:Arsenic photomultiplier transit
Pipe negative high voltage:240V;Arsenic lamp current:60mA;Mercury photomultiplier negative high voltage:240V;Mercury lamp electric current:60mA;Atomizer is high
Degree:10.0mm;Flow rate of carrier gas:300mL/min;And shield gas flow speed:800mL/min.Thus, it is possible to further improve detection
As a result the degree of accuracy.
Specifically, prepare liquid can be subjected to spectroscopic methodology detection in following manner, and is determined based on testing result to be measured
Total arsenic content and total mercury content in dairy products:
(a) blank solution is prepared
Prepare sample blank solution:Add the concentrated nitric acid that 4~5mL mass fractions are 65.0%~68.0%, 2mL mass point
Number is 30% hydrogen peroxide, shakes and is well mixed, and places and is cleared up in microwave dissolver, clears up and room temperature is cooled to after finishing, obtain
2.5mL aqueous sulfamic acids (concentration is 100g/L) are added to digestion solution, in digestion solution and are shaken up makes reaction completely, is neutralized
Neutralizer, is transferred in 25mL volumetric flasks by liquid with 5% hydrochloric acid after cooling, and adding 2.5mL thiourea solutions, (concentration is 50g/
L), with 5% hydrochloric acid solution constant volume, to obtain sample blank solution.
Prepare standard items blank solution:2.5mL thiourea solutions (concentration is 50g/L) are added into 25mL volumetric flasks, are used
5% hydrochloric acid solution constant volume, to obtain standard items blank solution.
(b) standard curve is made
1000 μ g/mL arsenic Standard Stock solutions are diluted to 100ng/mL, respectively into 6 25mL volumetric flasks add 0,
0.5th, 1.0,1.5, the 2.0, arsenic standard solution that 2.5mL concentration is 100 μ g/mL, with 5% hydrochloric acid solution wash bottle mouthful;By 1000 μ g/
ML mercury Standard Stock solutions are diluted to 10ng/mL, respectively into above-mentioned 6 25mL volumetric flasks add 0,0.5,1.0,1.5,2.0,
2.5mL concentration is 10ng/mL mercury standard solution, then with 5% hydrochloric acid solution wash bottle mouthful;Then hold respectively to above-mentioned 6 25mL
The sulfamic acid solution that 2.5mL concentration is 100g/L is added in measuring bottle, scale is settled to 5% hydrochloric acid solution, mixes, obtains
In standard liquid arsenic concentration be respectively 0,2.0,4.0,6.0,8.0,10.0ng/mL, mercury concentration is respectively 0,0.2,0.4,0.6,
0.8、1.0ng/mL。
Standard liquid and standard blank solution are introduced into AFS to be detected, using the fluorescence intensity that measures as
Ordinate, concentration is mapped for abscissa, respectively obtains arsenic concentration standard curve and mercury concentration standard curve, wherein, ordinate is glimmering
Luminous intensity is the difference that standard liquid fluorescence intensity subtracts standard blank solution fluorescence intensity.
(c) measure of prepare liquid
Under the same conditions, the prepare liquid based on 1.5mL, the boron that 2.5mL concentration is 15~20g/L is added into prepare liquid
Sodium hydride solution, and then prepare liquid and sample blank solution introducing AFS are detected, it is to be measured by what is measured
Liquid and sample blank solution fluorescence intensity bring calibration curve equation into, so as to obtain the arsenic in prepare liquid and sample blank solution and
The concentration of mercury.
(8) result of calculation
Arsenic and mercury content in dairy products to be measured is calculated based on following formula:
X=(c1-c0)×V/(m×1000)
Wherein,
X represents total arsenic or total mercury content in dairy products to be measured, and unit is mg/kg or mg/L;
c1The concentration of arsenic or mercury in prepare liquid is represented, unit is ng/mL;
c0The concentration of arsenic or mercury in sample blank solution is represented, unit is ng/mL;
M represents the quality or volume of dairy products to be measured, and unit is g or mL;
V represents the volume of digestion solution, and unit is mL.
Thus, embodiments in accordance with the present invention, this method removes the nitric acid in digestion solution, sulfamic acid using sulfamic acid
The nitrate ion in nitric acid, nitrite ion and volatile nitrogen oxide can be converted into nitrogen well, so that
Removal nitric acid purpose is reached, and then adds reducing agent the arsenic and mercury in neutralizer are converted into arsenic hydride and atomic state mercury, used
Two-channel atomic XRF detects the fluorescence intensity of arsenic and mercury respectively simultaneously, and determines dairy products to be measured based on testing result
In total arsenic content and total mercury content.This method removes the nitric acid in digestion solution by using sulfamic acid, it is to avoid nitric acid is with after
The continuous reducing agent reaction added makes sample discoloration, splash, and sulfamic acid not to be impacted to the fluorescence intensity of sample, so that
The degree of accuracy of testing result is improved, meanwhile, sulfamic acid is gentle with nitric acid reaction, simple to operate, it is possible thereby to substantially reduce inspection
Survey time-consuming.
Below with reference to specific embodiment, present invention is described, it is necessary to which explanation, these embodiments are only description
Property, without limiting the present invention in any way.
Embodiment 1
Total arsenic, total mercury content in following manner in detection dairy products
(1) sample pretreatment
In sampling and preparation process, it should be noted that do not make sample contamination;Solid sample carries out crushing uniform;Fresh sample exists
4 DEG C of refrigerations of refrigerator are standby.
(2) instrument, consumptive material, reagent
Instrument:
AFS-8220 AFSs;Electronic analytical balance (a ten thousandth);Microwave dissolver;Fume hood.
Consumptive material:
25mL, 100mL, 200mL, 500mL volumetric flask;1mL~10mL measuring pipettes.
Reagent:
Concentrated nitric acid (top pure grade, mass fraction be 65.0%~68.0%);Hydrogen peroxide (mass fraction is 30%);
2g/L sodium hydroxide solutions:2.0g sodium hydroxides are weighed, is dissolved with ultra-pure water and is settled to 1000mL;
15~20g/L sodium borohydride solutions:15.0~20.0g sodium borohydrides are weighed, with above-mentioned 2g/L sodium hydroxide solutions
Dissolve and be settled to 1000mL;
1000 μ g/mL arsenic Standard Stock solutions;
1000 μ g/mL mercury Standard Stock solutions;
100g/L sulfamic acid solutions:10g sulfamic acids are weighed, is dissolved with ultra-pure water and is settled to 100mL;
50g/L or 100g/L thiourea solutions:5g or 10g thiocarbamides are weighed, is dissolved with ultra-pure water and is settled to 100mL;
5% hydrochloric acid solution:Top grade pure hydrochloric acid 50mL is measured, 1000mL is diluted to ultra-pure water.
(3) AFS reference conditions
Arsenic photomultiplier negative high voltage:240V;
Arsenic lamp current:60mA;
Mercury photomultiplier negative high voltage:240V;
Mercury lamp electric current:60mA;
Atomizer height:10.0mm;
Flow rate of carrier gas:300mL/min;
Shield gas flow speed:800mL/min.
(4) sample digestion
0.2~2g (or mL) (being accurate to 0.0001g) sample is taken in digestion tube, adding 4~5mL mass fractions is
65.0%~68.0% concentrated nitric acid, 2mL mass fractions are 30% hydrogen peroxide, and shaking is well mixed, places micro-wave digestion
Cleared up in instrument, clear up and room temperature is cooled to after finishing, obtain adding 2.5mL aqueous sulfamic acid (concentration in digestion solution, digestion solution
For 100g/L) shake up make reaction completely, obtain neutralizer, neutralizer be transferred to 25mL volumetric flasks with 5% hydrochloric acid after cooling
In, 2.5mL thiourea solutions (concentration is 50g/L) are added, with 5% hydrochloric acid solution constant volume, are mixed, it is molten to obtain sample
Liquid, prepares upper machine testing after at least standing 30 minutes;Make blank test simultaneously.
(5) blank solution is prepared
Prepare sample blank solution:Add the concentrated nitric acid that 4~5mL mass fractions are 65.0%~68.0%, 2mL mass point
Number is 30% hydrogen peroxide, shakes and is well mixed, and places and is cleared up in microwave dissolver, clears up and room temperature is cooled to after finishing, obtain
2.5mL aqueous sulfamic acids (concentration is 100g/L) are added to digestion solution, in digestion solution and are shaken up makes reaction completely, is neutralized
Neutralizer, is transferred in 25mL volumetric flasks by liquid with 5% hydrochloric acid after cooling, and adding 2.5mL thiourea solutions, (concentration is 50g/
L), with 5% hydrochloric acid solution constant volume, to obtain sample blank solution.
Prepare standard items blank solution:2.5mL thiourea solutions (concentration is 50g/L) are added into 25mL volumetric flasks, are used
5% hydrochloric acid solution constant volume, to obtain standard items blank solution.
(6) standard curve is made
1000 μ g/mL arsenic Standard Stock solutions are diluted to 100ng/mL, respectively into 6 25mL volumetric flasks add 0,
0.5th, 1.0,1.5, the 2.0, arsenic standard solution that 2.5mL concentration is 100 μ g/mL, with 5% hydrochloric acid solution wash bottle mouthful;By 1000 μ g/
ML mercury Standard Stock solutions are diluted to 10ng/mL, respectively into above-mentioned 6 25mL volumetric flasks add 0,0.5,1.0,1.5,2.0,
2.5mL concentration is 10ng/mL mercury standard solution, then with 5% hydrochloric acid solution wash bottle mouthful;Then hold respectively to above-mentioned 6 25mL
The sulfamic acid solution that 2.5mL concentration is 100g/L is added in measuring bottle, scale is settled to 5% hydrochloric acid solution, mixes, obtains
In standard liquid arsenic concentration be respectively 0,2.0,4.0,6.0,8.0,10.0ng/mL, mercury concentration is respectively 0,0.2,0.4,0.6,
0.8、1.0ng/mL。
Standard liquid and standard blank solution are introduced into AFS to be detected, using the fluorescence intensity that measures as
Ordinate, concentration is mapped for abscissa, respectively obtains arsenic concentration standard curve and mercury concentration standard curve, wherein, ordinate is glimmering
Luminous intensity is the difference that standard liquid fluorescence intensity subtracts standard blank solution fluorescence intensity.
(7) measure of sample solution
Under the same conditions, the sample solution based on 1.5mL, it is 15~20g/L that 2.5mL concentration is added into sample solution
Sodium borohydride solution, and then sample solution and sample blank solution introduced into AFS detected, will measured
Sample solution and sample blank solution fluorescence intensity bring calibration curve equation into, it is molten to obtain sample solution and sample blank
The concentration of arsenic and mercury in liquid.
(8) result of calculation
Arsenic and mercury content in dairy products (sample) to be measured is calculated based on following formula:
X=(c1-c0)×V/(m×1000)
Wherein,
X represents total arsenic or total mercury content in dairy products to be measured, and unit is mg/kg or mg/L;
c1The concentration of arsenic or mercury in sample solution is represented, unit is ng/mL;
c0The concentration of arsenic or mercury in sample blank solution is represented, unit is ng/mL;
M represents the quality or volume of sample, and unit is g or mL;
V represents the volume of digestion solution, and unit is mL.
Embodiment 2
The total arsenic and total mercury content Comparative result obtained using the method detection of standard method and the present invention
Detect that the method for total arsenic content is performed according to GB 5009.11-2014 in standard method;
Detect that the method for total mercury content is performed according to GB 5009.17-2014 in standard method.
Contained using the method detection of standard method and the present invention with total arsenic in a batch of variety classes dairy products, total mercury
Amount, as a result as shown in table 1:
The testing result of table 1 is contrasted
As a result show, adopt the testing result being obtained by the present invention consistent with standard method result.
Embodiment 3
Investigate the rate of recovery of the method for the present invention
To add in background (dairy products for not containing arsenic and mercury) concentration be 0.0030mg/kg, 0.010mg/kg,
0.020mg/kg total mercury standard specimen and concentration is 0.01mg/kg, 0.05mg/kg, 0.10mg/kg total arsenic standard specimen, according to implementation
Total mercury and total arsenic content that method detection in example 1 is added in the background of various concentrations total mercury standard specimen and total arsenic standard specimen, and calculate
The rate of recovery,
As a result it is as shown in table 2:
The rate of recovery result of table 2
As a result show, the method total mercury rate of recovery of the invention is between 95.7%~105%, and total arsenic rate of recovery is 99.2%
Between~106%.
In addition, the detection of total mercury content is limited to 0.003mg/kg in standard method, the detection of total arsenic content is limited to 0.01mg/
Kg, is verified by mark-on, method of the invention total detection limit of Hg the rate of recovery 95.7%~98.7%, in total arsenic detection limit
The rate of recovery 103%~106%.
Embodiment 4
Investigate the precision of the method for the present invention
According to the detection method in embodiment 1, detection 11 times is repeated to same sample, and calculate the relative mark of testing result
Quasi- deviation (RSD), as a result as shown in table 3, the unit of total arsenic content and total mercury content is mg/kg in table.
The precision of table 3 investigates result
As a result show, method precision of the invention is good.
In the description of this specification, reference term " one embodiment ", " some embodiments ", " example ", " specifically show
The description of example " or " some examples " etc. means to combine specific features, structure, material or the spy that the embodiment or example are described
Point is contained at least one embodiment of the present invention or example.In this manual, to the schematic representation of above-mentioned term not
Identical embodiment or example must be directed to.Moreover, specific features, structure, material or the feature of description can be with office
Combined in an appropriate manner in one or more embodiments or example.In addition, in the case of not conflicting, the skill of this area
Art personnel can be tied the not be the same as Example or the feature of example and non-be the same as Example or example described in this specification
Close and combine.
Although embodiments of the invention have been shown and described above, it is to be understood that above-described embodiment is example
Property, it is impossible to limitation of the present invention is interpreted as, one of ordinary skill in the art within the scope of the invention can be to above-mentioned
Embodiment is changed, changed, replacing and modification.
Claims (8)
1. a kind of method for detecting total arsenic content and total mercury content in dairy products, it is characterised in that including:
By dairy products to be measured, nitric acid and hydrogen peroxide according to amount ratio (0.2~2.0g):(4~5mL):2.0mL is mixed and carried out
Micro-wave digestion, to obtain digestion solution;
Digestion solution described in 6mL is mixed with 2.5mL concentration for 100g/L sulfamic acid, to obtain neutralizer;
Neutralizer described in 8.5mL is mixed with 2.5mL concentration for 50g/L thiourea solution, to obtain prepare liquid;
Prepare liquid described in 1.5mL is mixed with 2.5mL concentration for 15~20g/L sodium borohydride solution, and it is former using binary channels
Sub- XRF detects to the prepare liquid, based on testing result determine total arsenic content in the dairy products to be measured and
Total mercury content,
Wherein, the testing conditions of the two-channel atomic XRF include:
Arsenic photomultiplier negative high voltage:240V;
Arsenic lamp current:60mA;
Mercury photomultiplier negative high voltage:240V;
Mercury lamp electric current:60mA;
Atomizer height:10.0mm;
Flow rate of carrier gas:300mL/min;And
Shield gas flow speed:800mL/min.
2. a kind of method for detecting total arsenic content and total mercury content in dairy products, it is characterised in that including:
Dairy products to be measured are subjected to micro-wave digestion, to obtain digestion solution;
The digestion solution is mixed with sulfamic acid, to obtain neutralizer;
The neutralizer is mixed with reducing agent, to obtain prepare liquid;And
The prepare liquid is subjected to spectroscopic methodology detection, and based on testing result determine total arsenic content in the dairy products to be measured and
Total mercury content.
3. method according to claim 2, it is characterised in that in advance by the dairy products to be measured, nitric acid and hydrogen peroxide
Mixed, and resulting mixed liquor be subjected to the micro-wave digestion,
Wherein, the amount ratio of the dairy products to be measured, the nitric acid and the hydrogen peroxide is (0.2~2.0g):(4~5mL):
2.0mL。
4. method according to claim 2, it is characterised in that the sulfamic acid concentration is 100g/L, based on described in 6mL
Digestion solution, the consumption of the sulfamic acid is 2.5mL.
5. method according to claim 2, it is characterised in that the neutralizer based on 8.5mL, the consumption of the reducing agent is
2.5mL。
6. method according to claim 5, it is characterised in that the reducing agent is included selected from the thiocarbamide that concentration is 50g/L
The aqueous solution and concentration are at least one of 15~20g/L sodium borohydride solution.
7. method according to claim 2, it is characterised in that using two-channel atomic XRF to the prepare liquid
Detected.
8. method according to claim 7, it is characterised in that the testing conditions bag of the two-channel atomic XRF
Include:
Arsenic photomultiplier negative high voltage:240V;
Arsenic lamp current:60mA;
Mercury photomultiplier negative high voltage:240V;
Mercury lamp electric current:60mA;
Atomizer height:10.0mm;
Flow rate of carrier gas:300mL/min;And
Shield gas flow speed:800mL/min.
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