Preparation method of standard molecules for the precise estimation of molecular weight cut-off of membranes by gel permeation chromatography

In this study, the weighted mass of standard molecular weight compounds (SMWC) was adopted to improve the accuracy of molecular weight distribution measured by the gel permeation chroma-tography (GPC). To evaluate the impact of SMWC compositions, the mixture prepared by constant, linear-weighted, and polynomial-weighted SMWC (3 g/L total) was used for the calibration of GPC, and results were confirmed with typical membrane-based size-exclusion experiments. The results obtained by GPC analysis revealed that the composition of SMWC in the feed significantly altered the final molecular weight cut-off (MWCO) of same membranes, and the polynomial-weighted SMWC provided the best match with the result of MWCO measured by the single-compound rejection experiment due to the enhanced signal intensity at the higher molecular weight compounds (>20,000 Da). Consequently, the preparation of SMWC in the polynomial manner should be suggested during the calibration and MWCO measurements of membranes by GPC.