Improvement of simultaneous determination of neutral monosaccharides and uronic acids by gas chromatography

•The gas chromatography method for simultaneous determination of uronic acids and neutral monosaccharides was improved.•Detailed discussions on derivatization and crucial conditions are presented.•The linearity, precision, accuracy and reproducibility of the improved method was investigated.

Although pre-column derivatization with n-propylamine and acetic anhydride combined with the gas chromatograph was a useful method for the analysis of monosaccharide composition, failure often occurs because of lack of detail information on the mechanism as well as the operating key point in derivatization process. In this study, the key points in the derivatization (lactonization time, the amount of n-propylamine and acetic anhydride) were investigated and optimized to improve the method. Under the optimal conditions, the derivatives of seven neutral monosaccharides and two uronic acids were simultaneouly obtained, after which they were well separated and detected by GC. It was also found that all derivatives of monosaccharides were stable even stored for 20 days. The linearity, sensitivity, precision, reproducibility and recovery rate of the improved method were evaluated. Thereafter, five polysaccharide samples from different sources were analyzed to validate the improved method.