Method of measuring lead content in shredded squid by microwave digestion-atomic absorption spectroscopy

A technique of atomic absorption spectroscopy and microwave digestion, which is applied in the field of quantitative analysis for the determination of lead in squid shreds, can solve the problems of unguaranteed accuracy, unsatisfactory signal stability, etc., and achieve high temperature rise and increased stability , the effect of improving the accuracy

Inactive Publication Date: 2014-01-08
SUZHOU GUOHUAN ENVIRONMENT DETECTION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

At present, the most commonly used determination method is atomic absorption spectrometry, especially graphite furnace atomic absorption spectrometry, which has the advantages of good repeatability, rapidity and convenience. However, for the determination of complex samples, especially those containing sodium chloride In high samples, the traditional graphite furnace atomic absorption spectrometry is always unsatisfactory for the determination of lead content, which is manifested in: poor signal stability and unguaranteed accuracy

Method used

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  • Method of measuring lead content in shredded squid by microwave digestion-atomic absorption spectroscopy
  • Method of measuring lead content in shredded squid by microwave digestion-atomic absorption spectroscopy
  • Method of measuring lead content in shredded squid by microwave digestion-atomic absorption spectroscopy

Examples

Experimental program
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Effect test

Embodiment 1

[0042] Accurately weigh 0.5g of crushed squid shredded sample into a clean and dry microwave digestion tank, add 6mL of 70% nitric acid and 2mL of 30% hydrogen peroxide, cover and seal it overnight, and put it into a microwave digestion apparatus with a digestion pressure of 2.5MPa the next day In the microwave digestion instrument, heat at 140°C for 5 minutes, 200°C for 5 minutes, 200°C for 20 minutes, and 0°C for 5 minutes to assist digestion. After the digestion program is over, take out the digestion tank and cool it to room temperature in a fume hood. Transfer the solution to a polytetrafluoroethylene beaker, wash the digestion tank several times with a small amount of water, put it into the beaker, place it on a hot plate to heat and catch the acid, and when the solution evaporates to 2mL, remove the beaker and transfer the test solution to a capacity of 25mL bottle, dilute to volume with twice distilled water to obtain a sample solution.

[0043] Drawing of working curv...

Embodiment 2

[0054]The only difference from Example 1 is that the matrix modifier added is 3.75uL 2% ammonium dihydrogen phosphate solution, 1.5uL 1% nitric acid solution, 0.75uL 1% ascorbic acid solution (that is, the volume ratio is 5:2:1)

[0055] Other experimental conditions are consistent with embodiment 1. Specifically:

[0056] Drawing of working curve:

[0057] Take 0.0, 5.0, 10.0, 15.0, 20.0, 25.0mL lead standard solution with a concentration of 0.05ug / mL in a 50mL volumetric flask, add 3.75uL 2% ammonium dihydrogen phosphate solution, 1.5uL 1% nitric acid solution, 0.75uL1 % ascorbic acid solution (i.e. the volume ratio is 3:2:1), constant volume with 1% nitric acid, the lead concentration A is 0.0mg / mL, 0.005ug / mL, 0.01ug / mL, 0.015ug / mL, 0.020ug / mL, 0.025ug / mL series of standard solutions, and then measure the absorbance C of the series of standard solutions according to the above-mentioned graphite furnace atomic absorption spectrometer measurement conditions, as follows: C=...

Embodiment 3

[0066] The difference from implementation 1 is that no matrix modifier is added.

[0067] Other other experimental conditions are consistent with embodiment 1. Specifically:

[0068] Drawing of working curve:

[0069] Take 0.0, 5.0, 10.0, 15.0, 20.0, 25.0mL of lead standard solution with a concentration of 0.05ug / mL in a 50mL volumetric flask, and dilute to volume with 1% nitric acid to obtain a lead concentration A of 0.0mg / mL respectively , 0.005ug / mL, 0.01ug / mL, 0.015ug / mL, 0.020ug / mL, 0.025ug / mL series of standard solutions, and then measure the absorbance C of the series of standard solutions according to the above-mentioned graphite furnace atomic absorption spectrometer measurement conditions , as follows: C=0, 0.63, 1.26, 1.89, 2.52, 3.15.

[0070] According to the corresponding relationship between A and C, a linear regression equation is obtained through mathematical fitting, as follows:

[0071] A=0.00794C (ug / mL), the correlation coefficient is r=0.9989.

[00...

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Abstract

The invention provides a method of measuring lead content in shredded squid by microwave digestion-atomic absorption spectroscopy. The method is characterized in that a shredded squid sample is pre-treated by adopting microwave digestion; mixed liquor of 2% ammonium dihydrogen phosphate liquor, 1% nitric acid liquor and 1% ascorbic acid liquor which are in a volume ratio of (3-5):2:1 is used as a matrix modifier; in an absorbance measuring process, the matrix modifier, sample liquor and standard liquor are measured at the same time, so that interferences of matrix can be lowered while lead is measured, accuracy of the measuring method can be improved, and signal stability can be increased. The whole test process is simple, sensitive and accurate, can be used for measuring the lead content in the shredded squid and is further widely applicable to a lead content test of diet consumables of drink, soy sauce, rice, flour, powered milk and the like in addition to being.

Description

technical field [0001] The invention relates to a quantitative analysis method for determining lead in shredded squid, in particular to a method for determining the lead content in shredded squid by means of microwave digestion and flame atomic absorption spectrometry of a matrix modifier. Background technique [0002] Squid has the advantages of high protein, low fat, and low calorie. Its nutritional value is not inferior to that of beef and tuna. Its processed products are also deeply loved by everyone, and shredded squid is one of them. Shredded squid is carefully processed through a strict processing industry. It is delicious, moderate in taste and rich in nutrition. It is a favorite snack food for modern people. Just because of this, the food safety problem of processed squid shredded product is more and more subject to the high attention of consumers in general. Therefore, accurate determination of the content of each element in the processed squid shredded product is...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N1/28G01N21/74
Inventor 徐晓华刘晓庆
Owner SUZHOU GUOHUAN ENVIRONMENT DETECTION
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