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Method for simultaneous detection of a plurality of content of non-protein nitrogen-containing compounds in milk by liquid chromatography-tandem mass spectrometry

A technology of liquid chromatography and tandem mass spectrometry, which is applied in the field of detection of the content of non-protein nitrogen-containing compounds, can solve the problem of single detection of non-protein nitrogen-containing compounds, and achieve a good linear relationship, improved accuracy, and strong sensitivity Effect

Active Publication Date: 2016-05-04
THE INSPECTION & QUARANTINE TECH CENT ZHEJIANG ENTRY EXIT INSPECTION & QUARANTINE BUREAU
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] The invention provides a method for simultaneously detecting the content of various non-protein nitrogenous compounds in milk by liquid chromatography tandem mass spectrometry, which solves the problem of single detection of non-protein nitrogenous compounds in the prior art

Method used

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  • Method for simultaneous detection of a plurality of content of non-protein nitrogen-containing compounds in milk by liquid chromatography-tandem mass spectrometry
  • Method for simultaneous detection of a plurality of content of non-protein nitrogen-containing compounds in milk by liquid chromatography-tandem mass spectrometry
  • Method for simultaneous detection of a plurality of content of non-protein nitrogen-containing compounds in milk by liquid chromatography-tandem mass spectrometry

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0077] The method for simultaneously detecting the content of multiple non-protein nitrogenous compounds in milk by liquid chromatography tandem mass spectrometry comprises the following steps:

[0078] (1) Pretreatment of samples to be tested:

[0079] Draw 1.00g of milk sample (accurate to 0.01g) into a 50mL stoppered centrifuge tube, add 100ng of melamine- 15 N 3 For the internal standard, add acetonitrile to 20mL, vortex, ultrasonic, high-speed centrifugation, take 10mL supernatant, add 7mL n-hexane, vortex, remove the upper n-hexane phase, concentrate the supernatant to nearly dryness, add 3mL volume fraction 5% ammoniacal acetonitrile solution (hereinafter referred to as 5% ammoniacal acetonitrile) is dissolved and vortexed to obtain the purified solution;

[0080] Add 5mL of 5% ammonia acetonitrile to the HLB solid phase extraction column for activation. After activation, pass the liquid to be purified through the HLB solid phase extraction column, collect the eluate ...

Embodiment 2

[0108] Embodiment 2 quantitative limit test

[0109] According to the signal response intensity and signal-to-noise ratio when adding 50 μg / kg of dexinil, dicyandiamide, biuret, cyromazine and melamine in milk (and whole milk), equal 10 with S / N Calculate and add five non-protein nitrogen-containing compounds in decinil, dicyandiamide, biuret, cyromazine and melamine, and finally determine the quantitative limit of non-protein nitrogen-containing compounds. The detection results are shown in Table 6.

[0110] Table 6 The detection method of the present invention is to the detection limit of quantification of each non-protein nitrogen-containing compound

[0111]

[0112] As can be seen from Table 6, the detection method of the present invention is far lower than the minimum limit standard (50 μ g / kg) at home and abroad to the detection quantitative limit of melamine, and also possesses lower detection quantitative limit to other four kinds of non-protein nitrogenous compoun...

Embodiment 3

[0113] Embodiment 3 recovery test

[0114] Add known amounts of dexinil, dicyandiamide, biuret, cyromazine, and melamine to blank skim milk (and whole milk) that do not contain the above five non-protein nitrogenous compounds, and follow the The method of embodiment 1 is done pretreatment to blank skimmed milk (and whole milk), according to the standard curve of embodiment 1, adopt the liquid chromatography tandem mass spectrometry condition of embodiment 1 to detect the content of each non-protein nitrogenous compound in the liquid to be tested content, the recovery test was carried out.

[0115] Recovery rate (%)=(recovery amount-content in sample) / scaling amount×100%;

[0116] Each test was repeated six times in parallel, and the recovery test results are shown in Table 7.

[0117] Five kinds of non-protein nitrogenous compounds added recovery and precision (n=6) in the sample of table 7

[0118]

[0119] As can be seen from Table 7, the overall recoveries of the five...

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Abstract

The present invention discloses a method for simultaneous detection of a plurality of content of non-protein nitrogen-containing compounds in milk by liquid chromatography-tandem mass spectrometry, the method is as follows: adding a protein precipitant into a to-be-tested sample, whirling, centrifuging, adding a degreasing agent into supernatant, whirling, centrifuging, removing a degreasing agent layer, concentrating a lower clearing liquid, dissolving with ammonia acetonitrile, whirling, performing column chromatography with a HLB solid phase extraction column, collecting an eluant, concentrating, dissolving with a liquid mixture of a 0.15% formic acid aqueous solution (containing 5mM of ammonium acetate) and acetonitrile in the volume ratio of 1: 9, and filtering to obtain a to-be-tested solution; preparing a standard mixing working solution series; respectively injecting the standard mixing working solution series and the to-be-tested solution under liquid chromatography-tandem mass spectrometry conditions, making a standard curve, and calculating the content of the non-protein nitrogen-containing compounds in the to-be-tested solution according to the standard curve. The method can be used to simultaneously detect the content of at least two of dicyclanil, dicyandiamide, biuret, cyromazine and melamine, and is high in accuracy and strong in sensitivity.

Description

technical field [0001] The invention relates to a method for detecting the content of non-protein nitrogenous compounds in dairy products, in particular to a method for simultaneously detecting the contents of various non-protein nitrogenous compounds in milk by liquid chromatography tandem mass spectrometry. Background technique [0002] Dairy products are one of the oldest natural beverages for human beings. Because of their rich nutrition, easy digestion and absorption, high quality and low price, and convenient consumption, they are also called "white blood". The most popular dairy products are milk and milk products. With the continuous improvement of the recognition of the nutritional value of milk, people's consumption demand for it is also increasing, and its quality requirements are also getting higher and higher. [0003] The nitrogen content of milk has always been an important indicator for judging the quality of milk. The determination method represented by the...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N30/88
CPCG01N30/88G01N2030/8809
Inventor 侯建波谢文张文华李杰陆顺祝泽龙姚滨滨
Owner THE INSPECTION & QUARANTINE TECH CENT ZHEJIANG ENTRY EXIT INSPECTION & QUARANTINE BUREAU
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