Analysis of Positional Isomers of α-Linked Glucooligosaccharidesby ρ -Aminobenzoic Acid Ethyl Ester-conversion Method

Abstract

A new method for simultaneously analyzing positional isomers of α-linked glucooligosaccharides was described. Four α-glucobioses (kojibiose, nigerose, maltose and isomaltose) were analyzed by using the p-aminobenzoic acid ethyl ester (ABEE)-conversion method under the following conditions: mobile phase, 0.1 M ammonium acetate buffer (pH 4.0) containing 12% acetonitrile; column temperature, 25°C. Furthermore a mixture of four α-glucobioses, five α-glucotrioses, 2²- ο -α -D-glucosyl-D-maltose (kojibiosyl glucose), 3²-ο-α-D-glucosyl-D-maltose (nigerosyl glucose), 4-ο -α-D-glucosyl-D-maltose (maltotriose), 6²-ο-α-D-glucosyl-D-maltose (panose), 6-ο-α-D-glucosyl-D-maltose (isomaltotriose) and glucose was able to be analyzed by using the ABEE-conversion method with 0.1 M ammonium acetate buffer (pH 4.0) containing 10.5% acetonitrile as an eluent and a column temperature of 25°C. This separation was further improved by connecting two col-umns in series. The relationship between the peak areas and quantities of ABEE-converted c-linked glucooligosaccharides was linear in the range of 30 pmol to 3 μmol.