Method for rapidly determining melamine in milk and dairy products by liquid chromatography-tandem mass spectrometry

Abstract

The invention discloses a method for rapidly determining melamine in milk and dairy products by liquid chromatography-tandem mass spectrometry (LC-MS / MS). According to the invention, an internal standard is added to a dairy product requiring detection; melamine is extracted by using acetonitrile; a normal-phase chromatographic column is adopted; a solution of acetonitrile and an ammonium acetate buffer salt is adopted as a mobile phase, and melamine is subject to reversed-phase separation; with tandem mass spectrometry, melamine in the milk and dairy products is subject to MRM qualitative and quantitative analysis. With a national standard method, purification is carried out by using an SPE columella, and a final constant volume is 1mL. With the rapid method provided by the invention, a final volume is 25mL. The adopted curve linearity range is 0.25ng*mL<-1> to 5.00ng*mL<-1>. When the value is multiplied 25 times the dilution difference, the value is 6.25mg / kg to 125mg / kg, which reaches and satisfies the requirement of the national standard. With the method, the sensitivity is improved, and the possibility of an overloaded sample is reduced.

Description

technical field [0001] The invention belongs to a method for rapidly determining melamine in milk and dairy products by liquid chromatography tandem mass spectrometry. Background technique [0002] As a chemical raw material, melamine can be used in the production of plastics, coatings, adhesives, and food packaging materials. Data show that melamine may enter food from the environment, food packaging bags, etc., and its content is very low. Melamine is not a food raw material, nor is it a food additive. It is forbidden to artificially add to feed and food. National standards [1] The limit of melamine is 1 mg / kg. In recent years, serious cases caused by the artificial addition of melamine have occurred from time to time [2-4] , so a fast and effective detection method for melamine is very necessary. [0003] At present, the Kjeldahl method is usually used in the world to determine the content of crude protein in feed, that is, the protein content is obtained by multiplyin...

AI Technical Summary

Problems solved by technology

Melamine has no practical effect, let alone any nutritional value

[0006]The temperament[7-9] method has good selectivity, but its pretreatment is too complicated and requires a long analysis time

Cannot adapt to occasions that need to process a large number of samples

[0007]High performance liquid chromatography[10-13]Compared with gas chromatography, it is relatively simple and fast. Many studies have shown that using reversed phase column For example, C18, C18 mixed column can effectively analyze melamine, but due to the limitation of column separation and detector, it is easy to produce false positive results

In addition, due to the sensitivity limit of the detector, the sample must be enriched with an extraction column, which increases the difficulty and cost of processing

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