Studies Of Detecting Phenyllactic Acid In The Food By Ion Chromatography

Phenyllactic acid is a kind of small natural molecule organic acids which exists in nature,with broad-spectrum antimicrobial activity,Pservatives,and its application in the food industry has a bright future.At present,the main detection methods of Phenyllactic acid are as follows:thin layer chromathenyllactic acid is a new type of biological preography,high performance liquid chromatography,gas chromatography,GC-MS method,Fourier transform mass spectrometry,etc.In alkali medium,phenllactic acid exists in the form of anion,which can be detected with alkali mobile phase,using anion exchange separation and a conductance detector inhibition.This study investigated the use of ion chromatography detection of benzene in food lactic acid.Fermented milk as experimental samples,first we studied and explored the pretreatment method of fermented dairy products,by comparing the ice acetic acid,methanol,acetonitrile precipitation effect of three kinds of precipitation agent,and Then we choosed the ice acetic acid as the best precipitation agent in this study and the amount of ice acetic acid as well.By comparing the different ion chromatographic columns separation efficiency as well as solid phase extraction column,organic modifier,the optimization of chromatographic conditions,we determined the detection of Phenyllactic acid in fermented milk.The chromatographic separation was established on Dionex IonPacAS16(4 mmx250 mm)anion exchange coloumn,using 2 mmol/LNaOH at 1.0 mL/-min in flow rate and a conductivity detector.The recovery percentages of the sample detection were 86.4%?95.8%.The detetion limit was 0.2 ?g/mL,and the RSD was less than 4.52%.The method provides good precision and reliable results of determination.Domestic mainstream fermented milk brand products as samples,through the standard addition recovery experiment ofsamples,to verify the chromatographic separation of Chapter 2 in the fermented milk and feasibility.And we also studied in the warranty period,changes of Phenyllactic acid in the samples.Chinese traditional kimchi as samples,the determination of Phenyllactic acid in kimchi was established based on Chapter 2,samples after high speed cetrifugation,and 0.22 ?m porous nylon membrane filtration to analysis.The chromatographic separation Was established on Dionex IonPacAS11(4 mmx250 mm)anion exchange coloumn,using 2 mmol/L NaOH at 1.0 mL/mm in flow rate and a Conductivity detector with the analysis time 20 min.The recovery percentages of the sample detection were 84.2%?92.27%.The detetion limit was 0.2 ?g/mL,the RSD was less than 4.2%.The method provides good precision and reliable results of determination.