Establishment And Application Of LC-MS/MS For The Detection Of ?- Dicardonyl Compounds

a- dicarbonyl compounds are intermediates between Maillard reaction and caramelizing reaction with high reactivity highly reactive. They are closely related to chronic diabetic complications and various diseases. In this paper, seven a- dicarbonyl compounds, including glucosone, 3-deoxyglucosone,3-deoxygalacosone, 3,4-dideoxyglucoson-3-ene,glyoxal,methylglyox, and 2,3-butanedione were studied. O-phenylenediamine was used as derivatizing agent, solid phase extraction was used to make the extraction solution purified.Using ion-pair compound for qualitative and quantitative, developed a sensitive and accurate method to detect seven a- dicarbonyl compounds at the same time in dairy products.The parameters of Liquid chromatography-electrospray-tandem mass spectrometry(LC-ESI-MS/MS) were optimized. A Polar-RP 80 A (2×150 mm, 4 ?m,Phenomenex )column was choosen to separated the analytes using a mobile phase of 0.1 % formic acid (A)and methanol (B) with the gradient elute program. The influences of the absolute matrix effect and the relative matrix effect on the target analysis were investigated in detail. It was found that the effect of the matrix effect on the target analysis was great. The targets were quantified by matrix curve of each sample. The linear range, detection limit and quantification limit of the method were established. The linearity of the matrix curve was in the range of 5 ?500 ?gL-1,R2 was above 0.99, the limits of detection and quantitation for each analyte in the standard solutions were 0.5?4?gL-1 and 1.8 ?12?gL-1.In the experiment.the precision of the method and stability of the sample are also studied. The results show that the precision withinday between 0.61 %?9.02 %, the precision of betweenday between 0.52 %?11.00 %. After the derivative of the sample can be placed at room temperature for two days, 4 ? for three days and -20 ? for five days.The content of seven analytes were investigated in 37 dairy products of different brands and types include the pure milk (including degreased or not), milk powder (infants, the elderly and family milk), brown lactobacillus beverage (original and low sugar) and fermented milk (plain and add flesh). In addition to GS and 3.4-DGE, other targets were detected in the sample, and the content was between 0.02?102.79 mg Kg-1. The content of 3.4-DGE in milk was between 0.21?5.81 mg Kg-1, and GS was not detected in milk. In other samples, the content of GS was between 0.19?225.13 mg Kg-1. The changes of ?-DCCs in milk powder under different brewing temperature and milk in different heating modes were also studied. Finally. we got the conclusion the best brewing temperature of milk powder is 50 ??70?,and milk heating method is hot water immersion or microwave heating for 1min.