Abstract: A method for the analysis of xylo-oligosaccharides(XOS) in xylo-oligosaccharide products, including xylobiose, xylotriose, xylotetraose, xylopentaose and xylohexaose, was developed using high performance anion-exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD). The retention times of xyloheptaose and xylooctaose were calculated according to the linear relationship between the retention time and the polymerization degree. The separation was performed on a CarboPacTM PA200 column (250 mm×3 mm) with a gradient elution of NaOH-NaOAc as the mobile phase. The calibration curves showed good linearity for the xylo-oligosaccharides in the range of 0.804~8.607 mg/L. The detection limits (LODs) and the quantification limits (LOQs) were 0.064~0.111 mg/L and 0.214~0.371 mg/L, respectively. Under the optimized conditions, the recoveries of xylo-oligosaccharides at three different spiked levels ranged from 84.29%~118.19%, with the relative standard deviations (RSDs, n=3) of 0.44%~14.87%. This method is fast and accurate for the quantitative analysis of the xylo-oligosaccharide products.

Key words: pulsed amperometric detection (PAD), xylo-oligosaccharides, high performance anion-exchange chromatography (HPAEC)