| With the recent recovery of domestic dairy industry,and high added value of organic milk,goat's milk,fruit milk and other products often fake and shoddy phenomenon,it is more important to strengthen the supervision and detection of adulteration.In rece nt years,Liquid Chromatography-Mass Spectrometry technology(Liquid Chromatography-Mass Spectrometry,LC-MS)due to its high selectivity,high sensitivity and good qualitative and quantitative analysis of the function as an integral part of food safety testing tool,in drug analysis,biochemical analysis,soil testing,environmental pollution,natural products analysis and the analysis of health food and agriculture,veterinary drug residue analysis,and many other fields has been widely used.In this paper,in the aspect of infant food quality identification,using liquid chromatography mass spectrometry,the research object of infant formula milk powder was studied as follows:1.An analytical method for the determination of the content of hippuric acid in infant formula by liquid chromatography mass spectrometry was established.The experimental results show that the mass concentration and peak area of hippuric acid have a good linear relationship with the concentration of 10 ~ 500ng/mL,and the correlation coefficient r=0.9998.The detection results were calculated by 3 times and 10 times of the SNR of the chromatographic baseline,and the detection limit(LOD)of the hippuric acid was 1ng/mL,and the quantitative limit was 5ng/mL;In the sample,the samples were added 10,20,and 100ng/mL with three levels of the hippuric acid sample solution,respectively.The results showed that the recovery rate of the hippuric acid was 80.4% ~ 107.9%,and the relative standard deviation(RSD)was 7.99% ~ 14.33%.Through actual sample testing,the judge hippuric acid content is not suitable as a biomarker for the characteristics of organic milk powder.According to related literature,although eat silage can also improve hippuric acid content,but considering the organic milk production enterprises mostly have through our agency certification of large organic farms,and grazing feed regulations have require ments,high levels of hippuric acid also can be used as organic milk a candidate markers of authenticity.2.This paper established a quantitative analysis method based on the content of beta-carotene,which was used to detect the mixture of milk powder in infant formula with liquid chromatography tandem mass spectrometry(LC-MS).Sample by potassium hydroxide solution saponification,petroleum ether extraction and nitrogen concentration,acetonitrile and methanol solution as mobile phase,Acclaim at Trinity Q1 chromatographic column(3.0 mmx50 mm,3.0 microns)reversed-phase liquid chromatography separation,positive ion scanning,multiple reaction monitoring(MRM)mode electrospray tandem mass spectrometry determination and confirmed,external standard method.The results showed that the beta Carotene(beta-Carotene)in the peak within 10 min,the method of quantitative limit of 1 mu g / 100 g,within 5 ~ 100 ng/mL has good linear relationship,the recovery was 80.4% ~ 107.9%,relative standard deviation(RSD)is 2.91% ~ 2.91%(n = 6).According to the linear relationship between the content of beta-carotene in the sample and the proportion of adulteration,a linear curve of mixing proportion was established to determine the proportion of milk powder mixed in the sample to achieve quantitative analysis.The method has the advantages of simple pretreatment,short detection period and high sensitivity.3.The content of chlorogenic acid was used as the characteristic index to test whether fruit milk was used as fruit juice in the fruit milk by lc-ms method.Established a liquid chromatography-tandem mass spectrometry method was developed for the determination of chlorogenic acid content in fruit milk,optimize the detection of chlorogenic acid in fruit milk pretreatment methods and equipment conditions,make the pretreatment method extracting effect is good,operation is simple and fast,the whole testing completed within 10 min.The test results show that the method has high accuracy and high sensitivity,which can satisfy the detection of chlorogenic acid in large quantities and can be used to verify the authenticity of fruit milk. |
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