Variations in bovine milk oligosaccharides after calving using p-aminobenzoic ethyl ester closed-ring labeling and negative ion electrospray LC/MS/MS   全文下載

Variations in bovine milk oligosaccharides after calving using p-aminobenzoic ethyl ester closed-ring labeling and negative ion electrospray LC/MS/MS

"A strategy was proposed to analyze bovine milk oligosaccharides using p-aminobenzoic ethyl ester (ABEE) closed-ringlabeling and C18 capillary liquid chromatography negative ion electrospray tandem mass spectrometry. Linkage specificfragment ions were used to identify oligosaccharide isomers. By constructing the mass chromatograms using linkagespecific fragment ions, isomers were differentiated based on m/z values as well as temporal separation provided byliquid chromatography. In addition to disialyllactose and the single isomer lacto-N-neohexaose, four pairs of linkageisomers including 3'/6'-sialyllactose (3'/6'-SL), 3'/6'-sialyllactosamine (3'/6'-SLN), 3'/6'-sialylgalactosyl-lactose (3'/6'-SGL), and lacto-N-tetraose/lacto-N-neotetraose (LNT/LNnT) in bovine milk were investigated. Variations of bovine milkoligosaccharides in a lactation period of 72 h after calving were studied. Sialylated oligosaccharide was found to bedistinctively more abundant in milk of the first 24 h, decreasing in successive milkings. For the first time, the variation oflacto-N-tetraose in bovine milk was reported."