An improved gas chromatographic method for measuring glucosamine and muramic acid concentrations

A method of simultaneously measuring glucosamine and muramic acid concentrations in marsh grass litter was developed. Spartina alterniflora samples were preextracted with acetone to remove lipids containing amino sugars and then hydrolyzed in 6 N HCl (100 degrees C, 4.5 h). Amino sugars in the hydrolysates were isolated by ion-exchange chromatography, which gave good recoveries (greater than 90%) and reproducibility (CV less than 5%). Isolated amino sugars were converted to O-methyloxime acetates. beta-Phenylglucose and N-methylglucamine were added as internal standards. Sample derivatives were quantified by capillary column gas chromatography. OV-101 and SE-54 capillary columns completely separated glucosamine and muramic acid from other amino sugars. The detection limit of glucosamine and muramic acid during gas chromatographic analysis was below 30 pmol using splitless-mode injection (SE-54 column). Filamentous fungal and procaryotic biomasses may be estimated simultaneously by using glucosamine and muramic acid biomass conversion factors in conjunction with this method.