Quantitative Analysis of Polysaccharides Using HPSEC-RID Based on Refractive Index Increment(dn/dc)

OBJECTIVE To establish a general method for quantitative analysis of polysaccharides using high performance size exclusion chromatography-refractive index detector(HPSEC-RID) based on refractive index increment dn/dc value. METHODS Based on the principle of concentration sensitive detector, the peak area of the sample component was linearly related to the concentration. The linear relationship between the peak area and concentration of aqueous sodium chloride solution, which had known dn/dc value(0.174 mL·g^-1), was used to calculate the calibration constant(K_RI). Furthermore, the quantitative analysis of polysaccharides was achieved independently without reference compounds multi-angle laser light scattering(MALLS) detector and third-party software. In this study, Lycium bararum polysaccharides were took as an example to compare the determination results obtained from the established method and method applied with third-party software individually. RESULTS The K_RI value was obtained with 0.998 in both offline and online modes based on aqueous sodium chloride solution with known dn/dc value. The determination results of Lycium barbarum polysaccharides in different batches of Lycium barbarum fruits using HPSEC-RID based on universal dn/dc value were consistent with the determination results by HPSEC-MALLS-RID, and RAD was ranged from 0.45%-1.23%. CONCLUSION The HPSEC-RID based on dn/dc value can realize the simple, rapid and accurate quantitative analysis of polysaccharides without reference compound, and not relying on MALLS detector and third-party software.