CN101650314A - Chroma detection method of tripolycyanamide contained in raw milk and milk product and kit - Google Patents
Chroma detection method of tripolycyanamide contained in raw milk and milk product and kit Download PDFInfo
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Abstract
The invention discloses a chroma detection method of tripolycyanamide contained in raw milk and milk products and a kit. The chroma detection method comprises the following steps: a. removing most proteins contained in a sample by an isoelectric point precipitation method and an organic solvent precipitation method, then regulating the pH value of the sample to be 2.0-3.0 by a hydrochloric acid solution, and using an obtained solution as a sample solution; b. adding the sample solution into a mercaptoacetic acid coating gold size solution, diluting the mixed solution by 0-10 times by water sothat the reaction concentration of the mercaptoacetic acid coating gold size solution is 1.9*10<-5> to 4.8*10<-5> mol/L, uniformly mixing the obtained solution to stand for 2-5 minutes under room temperature, visually observing the color change of the solution; and c. judging whether the sample contains the tripolycyanamide or not and judging the content range of the tripolycyanamide by the condition whether the color of the solution is changed or not and the change degree of the color. The kit comprises the mercaptoacetic acid coating gold size solution and a standard color comparison card. The chroma detection method and the kit have accurate detection and good reproducibility without using any expensive apparatus, simple, convenient and fast operation, low cost, easy master by common detectors and consumers and good application prospect.
Description
Technical field
The present invention relates to melamine detection method in raw milk and the dairy products, the particularly chroma detection method of melamine in raw milk and the dairy products, and the kit that is used for this method.
Background technology
Melamine is a kind of broad-spectrum Organic Chemicals, and topmost purposes is as the raw material of producing melamine formaldehyde resin, can also be used as fire retardant, water reducer, formaldehyde detersive etc.
Because the protein content of food is mainly estimated by measuring nitrogen content by China, and the nitrogen content of melamine is about 66%, the average nitrogen content 16% that is higher than protein far away, therefore, melamine is mixed in the food by illegal businessman, make the protein test content virtual height of food, thereby poor quality food is got by under false pretences.Zoopery is the result show, takes in the infringement that melamine can cause reproduction, urinary system for a long time, causes bladder, kidney portion calculus, and can further bring out carcinoma of urinary bladder.2007, the contamination accident of U.S. outburst pet food, post-survey show, mixed≤gluten powder of 6.6% melamine is that pet food causes the reason of poisoning.2008, the contaminated incident of China's outburst Sanlu baby milk powder, the infant who has caused eating contaminated milk powder produces the kidney stone illness, and its reason also is to contain melamine in the milk powder.
The melamine detection method mainly contains high performance liquid chromatography, liquid chromatography-tandem mass spectrometry method, gas chromatography-tandem mass spectrometry etc. in existing raw milk and the dairy products.Though these methods can realize the accurate detection of melamine, it needs exact instrument and professional's operation, and consuming time longer, testing cost is higher, is difficult to popularize in most of food production enterprise and ordinary consumer.Therefore, the Ministry of Science and Technology collects the technology and the product of melamine in the fast detecting raw material milk and milk products towards the society, and proposes three requirements: accurate to melamine detection, detectability is less than or equal to 2 milligrams/per kilogram or every liter, favorable reproducibility; Be fit to on-the-spot, fast detecting, on average each sample detection time was less than 30 minutes (comprising time for sample pretreatment); Technical products or instrument and equipment cost are lower, and operating cost is low.
Summary of the invention
In view of this, one of purpose of the present invention is to provide the chroma detection method of melamine in a kind of raw milk and the dairy products, have and detect accurately, favorable reproducibility, do not need to use any expensive instrument, easy and simple to handle fast, characteristics such as cost is low, be easy to help actual promotion and application for common testing staff and consumer's grasp; Two of purpose is to provide a kind of kit that is used for raw milk and dairy products melamine chroma detection method.
For achieving the above object, in a first aspect of the present invention, provide the chroma detection method of melamine in a kind of raw milk and the dairy products, comprise the steps:
The pre-treatment of a, sample
Get the aqueous solution of raw milk or liquid dairy products or solid dairy products, regulate pH with hydrochloric acid solution and make the casein precipitation to caseic isoelectric point, the centrifuging and taking supernatant, add ethanol again and make all the other protein denaturation precipitations, the centrifuging and taking supernatant, regulate pH to 2.0～3.0 with hydrochloric acid solution, as sample solution;
The detection of b, sample solution
Add step a gained sample solution in solution colour is the gold size solution of red mercaptoacetic acid bag quilt, it is 1.9 * 10 that dilute with water makes the reaction density of the gold size of mercaptoacetic acid bag quilt for 0～10 times
-5～4.8 * 10
-5Mol/L, mixing left standstill the variation of visualization solution colour 2～5 minutes under the room temperature;
C, result judge
If step b gained solution colour becomes lavender or blueness or mazarine by redness, then judge and contain melamine in the sample; If step b gained solution colour still is red, then judge the melamine that does not contain melamine in the sample or only contain low content.
Further, said method comprising the steps of:
The pre-treatment of a, sample
Get the aqueous solution of raw milk or liquid dairy products or solid dairy products, regulate pH with hydrochloric acid solution and make casein precipitation, centrifuging and taking supernatant to caseic isoelectric point, add ethanol again and make all the other protein denaturation precipitations, the centrifuging and taking supernatant is regulated pH to 2.0 with hydrochloric acid solution, as sample solution;
The detection of b, sample solution
Add step a gained sample solution in solution colour is the gold size solution of red mercaptoacetic acid bag quilt, it is 3.8 * 10 that dilute with water makes the reaction density of the gold size of mercaptoacetic acid bag quilt for 0～10 times
-5Mol/L, mixing left standstill the variation of visualization solution colour 3 minutes under the room temperature;
C, result judge
Colorimetric card in step b gained solution colour and the kit is contrasted, if step b gained solution colour becomes lavender or blueness or mazarine by redness, then judge and contain melamine in the sample: if step b gained solution colour becomes lavender by redness, then the concentration c of melamine is 0.8mg/L≤c≤1.7mg/L in the determination step b gained solution; If step b gained solution colour becomes blueness by redness, then the concentration c of melamine is 1.7mg/L＜c＜2.5mg/L in the determination step b gained solution; If step b gained solution colour becomes mazarine by redness, then in the determination step b gained solution concentration of melamine greater than 2.5mg/L;
If step b gained solution colour still is red, then judge the melamine that does not contain melamine in the sample or only contain low content: the concentration c of melamine is 0mg/L≤c＜0.8mg/L in the step b gained solution;
According to the concentration of melamine and total extension rate of sample in the step b gained solution, can calculate the content range of melamine in the sample.
Further, the gold size solution of described mercaptoacetic acid bag quilt can be obtained by following method: chlorauric acid solution is mixed with mercaptoacetic acid solution, regulate pH to 6～7 with sodium hydroxide solution, drip the borane reducing agent sodium hydride solution, stirring reaction under the room temperature, the red clear solution of gained is the gold size solution of mercaptoacetic acid bag quilt.
In a second aspect of the present invention, a kind of kit that is used for raw milk and dairy products melamine chroma detection method is provided, described kit comprises the gold size solution and the standard color comparison card of mercaptoacetic acid bag quilt.
Beneficial effect of the present invention is: detection method of the present invention is the colourity half-quantitative detection, change color and intensity of variation by reactant liquor, but the having or not of melamine in the judgement sample not only, but and the content range of melamine in the judgement sample, detect accurately, favorable reproducibility, do not need to use any expensive instrument, cost is low, and is easy and simple to handle quick, be easy to help actual promotion and application for common testing staff and consumer's grasp.Detection kit cost of the present invention is low, easy to use, has good market outlook.
Description of drawings
Fig. 1 is the gold size of mercaptoacetic acid bag quilt and the visible absorption spectra figure of melamine effect; Wherein: curve 1 is the visible absorption spectra (blank) of the gold size solution of mercaptoacetic acid bag quilt, curve 2 is the visible absorption spectra (negative control) of 2.0 hydrochloric acid solution effect for the gold size solution of mercaptoacetic acid bag quilt and pH, curve 3～5 is that 2.0 concentration is respectively 1.6 for the gold size solution of mercaptoacetic acid bag quilt and pH, 1.8, the visible absorption spectra of the melamine solution effect of 2.5mg/L.
Fig. 2 is that the acidity of sample solution is optimized the result.
Fig. 3 is that the reaction density of the gold size of mercaptoacetic acid bag quilt is optimized the result.
Fig. 4 is the synoptic diagram that concerns between melamine concentration and the gold size maximum absorption wavelength.
Embodiment
In order to make the purpose, technical solutions and advantages of the present invention clearer, the preferred embodiments of the present invention are described in detail below in conjunction with accompanying drawing.
The existing lot of documents report of the preparation method of the gold size solution of the mercaptoacetic acid bag quilt that the present invention uses, the gold size solution of the mercaptoacetic acid bag quilt that uses in the preferred embodiment is reference literature method (Xu Jiaozhen etc., the pH value is to the influence of mercaptan gold nano-particles modified aggregative state, chemical research, 2003,14 (4): 16-18) make: getting concentration is the chlorauric acid solution 2ml of 12mmol/L, adding water 50ml and concentration is the mercaptoacetic acid solution 260 μ l of 10mmol/L, with concentration is sodium hydroxide solution adjusting pH to 6～7 of 0.02mol/L, thin up is to 99ml, mixing, the massfraction that drips new system is 1% sodium borohydride solution 1ml, stirring reaction is 3 hours under the room temperature, the red clear solution of gained is the gold size solution of mercaptoacetic acid bag quilt, the maximum absorption wavelength that records solution with ultraviolet spectrophotometer is 518nm, calculates gold size concentration according to the consumption and the overall solution volume of gold chloride.
1, the foundation of melamine chroma detection method in raw milk and the dairy products
(1) spectral signature of the gold size of mercaptoacetic acid bag quilt and melamine reaction
Getting concentration is 2.4 * 10
-4The gold size solution 400 μ l of the mercaptoacetic acid bag quilt of mol/L add the melamine solution 250 μ l that regulate the variable concentrations of pH to 2.0 with hydrochloric acid solution, and (reaction density of the gold size of mercaptoacetic acid bag quilt is 3.8 * 10 to 2.5ml with distilled water diluting
-5Mol/L, the reaction density of melamine be respectively 1.6,1.8 and 2.5mg/L); Establish blank (not adding melamine solution) and negative control (is that 2.0 hydrochloric acid solution substitutes melamine solution with pH) simultaneously; Left standstill under the room temperature 3 minutes, and scanned visible absorption spectra with spectrophotometer.
The result as shown in Figure 1, compare with blank, the gold size maximum absorption wavelength of negative control does not change, and after in the gold size solution of mercaptoacetic acid bag quilt, adding the melamine solution that pH is 2.0 variable concentrations, the maximum absorption wavelength generation red shift of gold size, peak shape broadens, and along with the increase of melamine concentration, the degree that red shift of wavelength and peak shape broaden increases gradually, and solution colour is gradually changed by redness → lavender → blueness → mazarine.Infer that its reaction mechanism is as follows: mercaptoacetic acid is coated on the gold size surface by the Au-S key, and its carboxyl is exposed outside, when pH value of solution near when neutral mainly with COO
-Form exist; And the amino of melamine when pH value of solution is 2.0 mainly with NH
3 +Form exist; After in the gold size solution of mercaptoacetic acid bag quilt, adding pH and be 2.0 melamine solution, the COO on gold size surface
-NH with melamine
3 +By the electrostatic interaction combination, the distance between the gold size of furthering, thus making the maximum absorption wavelength generation red shift of gold size, peak shape broadens.
(2) the acidity optimization of sample solution
Getting concentration is 2.4 * 10
-4The gold size solution 400 μ l of the mercaptoacetic acid bag quilt of mol/L add different pH and (are respectively 1.2,1.5,1.8,1.9,2.0,3.1,4.3 and 5.5) hydrochloric acid solution 250 μ l, (reaction density of the gold size of mercaptoacetic acid bag quilt is 3.8 * 10 to 2.5ml with distilled water diluting
-5Mol/L), left standstill under the room temperature 3 minutes, scan visible absorption spectra with spectrophotometer, the maximum absorption wavelength of record gold size, and compare with blank (not adding hydrochloric acid solution), calculate the red shift value (Δ λ) of maximum absorption wavelength, the pH with hydrochloric acid solution is a horizontal ordinate again, and the red shift value of maximum absorption wavelength (Δ λ) is the ordinate curve plotting.
The result as shown in Figure 2, in the gold size solution of mercaptoacetic acid bag quilt, add the hydrochloric acid solution of pH 〉=2.0 after, the maximum absorption wavelength of gold size does not change; And after in the gold size solution of mercaptoacetic acid bag quilt, adding the hydrochloric acid solution of pH＜2.0, the maximum absorption wavelength generation red shift of gold size, and the red shift degree reduces and increases gradually along with pH.Infer that its reaction mechanism is as follows: when the near neutrality of pH value of solution, the carboxyl on gold size surface is mainly with COO
-Form have COO
-Between the electrostatic repulsion effect make gold size be stable disperse state; When pH value of solution reduces, COO
-Can be gradually and H
+In conjunction with forming COOH, can be between the COOH by further distance between the gold size of hydrogen bond action, thus make the maximum absorption wavelength generation red shift of gold size.Therefore, for fear of the interference of hydrochloric acid to testing result itself, guarantee that again melamine is protonated as much as possible simultaneously, the acidity of sample solution is preferably pH 2.0～3.0, most preferably is 2.0.
(3) the reaction density optimization of the gold size of mercaptoacetic acid bag quilt
Get the gold size solution 400 μ l of the mercaptoacetic acid bag quilt of variable concentrations, add the melamine solution 250 μ l that regulate pH to 2.0 with hydrochloric acid solution, be respectively 1.0 with distilled water diluting to the reaction density of the gold size of 2.5ml[mercaptoacetic acid bag quilt, 1.9,2.9,3.8,4.8,5.8,6.7 (* 10
-5) mol/L, the reaction density of melamine is 1.6mg/L], left standstill under the room temperature 3 minutes, scan visible absorption spectra with spectrophotometer, the maximum absorption wavelength of record gold size, and compare with negative control (is that 2.0 hydrochloric acid solution substitutes melamine solution with pH), the red shift value (Δ λ) of maximum absorption wavelength calculated, reaction density (c) with the gold size of mercaptoacetic acid bag quilt is a horizontal ordinate again, and the red shift value of maximum absorption wavelength (Δ λ) is the ordinate curve plotting.
The result as shown in Figure 3, with negative control relatively, when reaction density c 〉=4.8 * 10 of the gold size of mercaptoacetic acid bag quilt
-5During mol/L, the maximum absorption wavelength of gold size does not change; And when reaction density c＜4.8 * 10 of the gold size of mercaptoacetic acid bag quilt
-5During mol/L, the maximum absorption wavelength generation red shift of gold size, and the red shift degree reduces and increases gradually along with concentration; But reaction density c＜1.9 * 10 of the gold size of mercaptoacetic acid bag quilt
-5During mol/L, solution colour is very shallow, is unfavorable for the colourity observation; Therefore, take all factors into consideration, the reaction density of the gold size of mercaptoacetic acid bag quilt is preferably 1.9 * 10
-5～4.8 * 10
-5Mol/L most preferably is 3.8 * 10
-5Mol/L.
(4) relation between melamine concentration and the gold size maximum absorption wavelength
Get the gold size solution 400 μ l of mercaptoacetic acid bag quilt, add the melamine solution 250 μ l that regulate the variable concentrations of pH to 2.0 with hydrochloric acid solution, (reaction density of the gold size of mercaptoacetic acid bag quilt is 3.8 * 10 to 2.5ml with distilled water diluting
-5Mol/L, the reaction density of melamine is respectively 0.8,1.2, and 1.6,1.7,1.8,1.9,2.1,2.5,2.9,3.4,3.8,4.2 and 4.6mg/L), left standstill under the room temperature 3 minutes, and scanned visible absorption spectra, the maximum absorption wavelength of record gold size with spectrophotometer, and compare with negative control (is that 2.0 hydrochloric acid solution substitutes melamine solution with pH), calculate the red shift value (Δ λ) of maximum absorption wavelength, the reaction density (c) with melamine is a horizontal ordinate again, and the red shift value of maximum absorption wavelength (Δ λ) is drawn scatter diagram for ordinate.
The result as shown in Figure 4, with negative control relatively, when the reaction density c of melamine＜0.8mg/L, the maximum absorption wavelength of gold size does not change, solution colour still be a redness; When the reaction density c of melamine is 0.8mg/L≤c≤1.7mg/L, the equal red shift 2nm of the maximum absorption wavelength of gold size, solution colour becomes lavender by redness; When the reaction density c of melamine is 1.7mg/L＜c＜2.5mg/L, the maximum absorption wavelength red shift 2～12nm (not comprising 2nm and 12nm) of gold size, solution colour becomes blueness by redness; When the reaction density c of melamine 〉=2.5mg/L, the equal red shift 12nm of the maximum absorption wavelength of gold size, solution colour becomes mazarine by redness.
(5) chroma detection method of melamine in raw milk and the dairy products
According to above-mentioned experimental result and optimized reaction conditions, set up the chroma detection method of melamine in raw milk and the dairy products, may further comprise the steps:
The pre-treatment of a, sample
Get the aqueous solution of raw milk or liquid dairy products or solid dairy products, regulate pH with hydrochloric acid solution and make the casein precipitation to caseic isoelectric point, the centrifuging and taking supernatant, add ethanol again and make all the other protein denaturation precipitations, the centrifuging and taking supernatant, regulate pH to 2.0～3.0 with hydrochloric acid solution, as sample solution;
The detection of b, sample solution
Add step a gained sample solution in solution colour is the gold size solution of red mercaptoacetic acid bag quilt, it is 1.9 * 10 that dilute with water makes the reaction density of the gold size of mercaptoacetic acid bag quilt for 0～10 times
-5～4.8 * 10
-5Mol/L, mixing left standstill the variation of visualization solution colour 2～5 minutes under the room temperature;
C, result judge
If step b gained solution colour becomes lavender or blueness or mazarine by redness, then judge and contain melamine in the sample; If step b gained solution colour still is red, then judge the melamine that does not contain melamine in the sample or only contain low content.
Further, on the said method basis, according to most preferred reaction conditions, the chroma detection method of melamine may further comprise the steps in raw milk and the dairy products:
The pre-treatment of a, sample
Get the aqueous solution of raw milk or liquid dairy products or solid dairy products, regulate pH with hydrochloric acid solution and make casein precipitation, centrifuging and taking supernatant to caseic isoelectric point, add ethanol again and make all the other protein denaturation precipitations, the centrifuging and taking supernatant is regulated pH to 2.0 with hydrochloric acid solution, as sample solution;
The detection of b, sample solution
Add step a gained sample solution in solution colour is the gold size solution of red mercaptoacetic acid bag quilt, it is 3.8 * 10 that dilute with water makes the reaction density of the gold size of mercaptoacetic acid bag quilt for 0～10 times
-5Mol/L, mixing left standstill the variation of visualization solution colour 3 minutes under the room temperature;
C, result judge
Colorimetric card in step b gained solution colour and the kit is contrasted, if step b gained solution colour becomes lavender or blueness or mazarine by redness, then judge and contain melamine in the sample: if step b gained solution colour becomes lavender by redness, then the concentration c of melamine is 0.8mg/L≤c≤1.7mg/L in the determination step b gained solution; If step b gained solution colour becomes blueness by redness, then the concentration c of melamine is 1.7mg/L＜c＜2.5mg/L in the determination step b gained solution; If step b gained solution colour becomes mazarine by redness, then in the determination step b gained solution concentration of melamine greater than 2.5mg/L;
If step b gained solution colour still is red, then judge the melamine that does not contain melamine in the sample or only contain low content: the concentration c of melamine is 0mg/L≤c＜0.8mg/L in the step b gained solution;
According to the concentration of melamine and total extension rate of sample in the step b gained solution, can calculate the content range of melamine in the sample.
Certainly, in order to understand the concentration range of melamine in the sample more accurately,, detect according to step a～c again after can increasing the dilution of sample multiple if step b gained solution colour becomes mazarine by redness; If step b gained solution colour still is red, can dwindles the dilution of sample multiple or will detect according to step a～c again after the sample concentration.
In said method, adopt isoelectric point precipitation to carry out sample pre-treatments (separating most of protein of removing in the sample) with organic solvent precipitation method: caseic content accounts for 80～82% of total protein content in raw milk and the dairy products, remove casein so adopt isoelectric point precipitation earlier, adopt organic solvent precipitation method to remove other residual protein again, when guaranteeing the purification sample, can avoid mixing of new interference impurity.
2, the kit that is used for raw milk and dairy products melamine chroma detection method
Chroma detection method according to melamine in raw milk of setting up and the dairy products can prepare the kit that is used for raw milk and dairy products melamine chroma detection method, and this kit comprises the gold size solution of mercaptoacetic acid bag quilt.In addition,, make tester's color of determining step b gained solution more accurately, also comprise standard color comparison card in this kit for unified color standard.
3, the application of melamine chroma detection method and detection kit thereof in raw milk and the dairy products
(1) contains the detection of the milk powder of melamine
Get known milk powder (the board baby formula milk powder of bestowing favour that contains melamine, lot number 4161080187700238) 3g, add distilled water 30ml and make dissolving, with concentrated hydrochloric acid regulator solution pH to 4.6, standing demix, the centrifuging and taking supernatant, add ethanol 10ml again, standing demix, centrifuging and taking supernatant, with concentration be the hydrochloric acid solution of 0.02mol/L to regulate pH be 2.0, as sample solution;
Getting concentration is 2.4 * 10
-4The gold size solution 400 μ l of the mercaptoacetic acid bag quilt of mol/L, add sample solution 250 μ l, with distilled water diluting to 2.5ml, left standstill under the room temperature 3 minutes, visualization, solution colour becomes lavender by redness, show and contain the melamine that concentration is 0.8～1.7mg/L in the solution, extension rate per sample, the content that calculates melamine in this milk powder is 16.3mg/kg, result (17mg/kg) basically identical that detects with the employing high performance liquid chromatography of State General Administration for Quality Supervision report.
(2) do not contain the detection of the milk powder of melamine
Get known milk powder (the big babies ' formula milk powder of the sharp board of refined scholar that does not contain melamine, lot number: 2548584479516281) 3g, add distilled water 30ml and make dissolving, with concentrated hydrochloric acid regulator solution pH to 4.6, standing demix, the centrifuging and taking supernatant, add ethanol 10ml again, standing demix, centrifuging and taking supernatant, with concentration be the hydrochloric acid solution of 0.02mol/L to regulate pH be 2.0, as sample solution;
Getting concentration is 2.4 * 10
-4The gold size solution 400 μ l of the mercaptoacetic acid bag quilt of mol/L, add sample solution 250 μ l, with distilled water diluting to 2.5ml, left standstill under the room temperature 3 minutes, visualization, solution colour does not change, and shows not contain melamine in the sample basically identical as a result that detects with the employing high performance liquid chromatography of State General Administration for Quality Supervision report.
Explanation is at last, above embodiment is only unrestricted in order to technical scheme of the present invention to be described, although by invention has been described with reference to the preferred embodiments of the present invention, but those of ordinary skill in the art is to be understood that, can make various changes to it in the form and details, and the spirit and scope of the present invention that do not depart from appended claims and limited.
Claims (4)
1, the chroma detection method of melamine in raw milk and the dairy products is characterized in that: may further comprise the steps:
The pre-treatment of a, sample
Get the aqueous solution of raw milk or liquid dairy products or solid dairy products, regulate pH with hydrochloric acid solution and make the casein precipitation to caseic isoelectric point, the centrifuging and taking supernatant, add ethanol again and make all the other protein denaturation precipitations, the centrifuging and taking supernatant, regulate pH to 2.0～3.0 with hydrochloric acid solution, as sample solution;
The detection of b, sample solution
Add step a gained sample solution in solution colour is the gold size solution of red mercaptoacetic acid bag quilt, it is 1.9 * 10 that dilute with water makes the reaction density of the gold size of mercaptoacetic acid bag quilt for 0～10 times
-5～4.8 * 10
-5Mol/L, mixing left standstill the variation of visualization solution colour 2～5 minutes under the room temperature;
C, result judge
If step b gained solution colour becomes lavender or blueness or mazarine by redness, then judge and contain melamine in the sample; If step b gained solution colour still is red, then judge the melamine that does not contain melamine in the sample or only contain low content.
2, the chroma detection method of melamine in raw milk according to claim 1 and the dairy products is characterized in that: may further comprise the steps:
The pre-treatment of a, sample
Get the aqueous solution of raw milk or liquid dairy products or solid dairy products, regulate pH with hydrochloric acid solution and make casein precipitation, centrifuging and taking supernatant to caseic isoelectric point, add ethanol again and make all the other protein denaturation precipitations, the centrifuging and taking supernatant is regulated pH to 2.0 with hydrochloric acid solution, as sample solution;
The detection of b, sample solution
Add step a gained sample solution in solution colour is the gold size solution of red mercaptoacetic acid bag quilt, it is 3.8 * 10 that dilute with water makes the reaction density of the gold size of mercaptoacetic acid bag quilt for 0～10 times
-5Mol/L, mixing left standstill the variation of visualization solution colour 3 minutes under the room temperature;
C, result judge
Colorimetric card in step b gained solution colour and the kit is contrasted, if step b gained solution colour becomes lavender or blueness or mazarine by redness, then judge and contain melamine in the sample: if step b gained solution colour becomes lavender by redness, then the concentration c of melamine is 0.8mg/L≤c≤1.7mg/L in the determination step b gained solution; If step b gained solution colour becomes blueness by redness, then the concentration c of melamine is 1.7mg/L＜c＜2.5mg/L in the determination step b gained solution; If step b gained solution colour becomes mazarine by redness, then in the determination step b gained solution concentration of melamine greater than 2.5mg/L;
If step b gained solution colour still is red, then judge the melamine that does not contain melamine in the sample or only contain low content: the concentration c of melamine is 0mg/L≤c＜0.8mg/L in the step b gained solution;
According to the concentration of melamine and total extension rate of sample in the step b gained solution, can calculate the content range of melamine in the sample.
3, the chroma detection method of melamine in raw milk according to claim 1 and 2 and the dairy products, it is characterized in that: chlorauric acid solution is mixed with mercaptoacetic acid solution, regulate pH to 6～7 with sodium hydroxide solution, drip the borane reducing agent sodium hydride solution, stirring reaction under the room temperature, the red clear solution of gained is the gold size solution of mercaptoacetic acid bag quilt.
4, be used for the kit of described raw milk of claim 1 and dairy products melamine chroma detection method, it is characterized in that: described kit comprises the gold size solution and the standard color comparison card of mercaptoacetic acid bag quilt.
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| CN102262163A (en) * | 2011-05-04 | 2011-11-30 | 四川大学 | Rapid and automatic determination method and device for tripolycyanamide content in dairy products |
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| CN103487436A (en) * | 2013-10-15 | 2014-01-01 | 无锡艾科瑞思产品设计与研究有限公司 | Quantitative detection method of melamine chromaticity in raw milk and dairy products |
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| KR100935703B1 (en) * | 2008-01-14 | 2010-01-07 | 대한민국 | Device and method analyzing milk for field |
| CN101387644A (en) * | 2008-09-27 | 2009-03-18 | 武汉工业学院 | Melamine immune chromatography test paper detecting method |
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| CN101413917A (en) * | 2008-10-31 | 2009-04-22 | 扬州大学 | Electrochemical fast detecting method of melamine in dairy produce |
| CN101509910B (en) * | 2009-03-20 | 2011-06-22 | 兰州大学 | Reagent and method for rapidly detecting melamine in liquid milk |
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| CN102313733A (en) * | 2010-07-05 | 2012-01-11 | 中国石油集团川庆钻探工程有限公司川东钻探公司 | Method for rapid testing hydrogen sulfide content in drilling fluid |
| CN102313733B (en) * | 2010-07-05 | 2013-07-31 | 中国石油集团川庆钻探工程有限公司川东钻探公司 | Method for rapid testing hydrogen sulfide content in drilling fluid |
| CN102109469A (en) * | 2011-03-15 | 2011-06-29 | 中国人民解放军军事医学科学院卫生学环境医学研究所 | Kit and method for detecting melamine by virtue of fast visual colorimetry |
| CN102262163A (en) * | 2011-05-04 | 2011-11-30 | 四川大学 | Rapid and automatic determination method and device for tripolycyanamide content in dairy products |
| CN102262163B (en) * | 2011-05-04 | 2013-08-21 | 四川大学 | Rapid and automatic determination method and device for tripolycyanamide content in dairy products |
| CN103487436A (en) * | 2013-10-15 | 2014-01-01 | 无锡艾科瑞思产品设计与研究有限公司 | Quantitative detection method of melamine chromaticity in raw milk and dairy products |
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