Inter-laboratory evaluation of SEC-post-column calcofluor for determination of the weight-average molar mass of cereal β-glucan

Even though size exclusion chromatography (SEC) with post column addition of calcofluor (SEC-calcofluor) has been used for the determination of cereal beta-glucan molar mass in foods for many years, there is a lack of systematic evaluation of the method. To address this issue a set of suitable beta-glucan standards were generated by preparative SEC and their molar mass characteristics were determined by analytical multi-detection SEC (refractive index (RI), light scattering). Each standard was then analysed by SEC-calcofluor at three different labs. As a direct comparison, the analyses were repeated with a RI detector. For SEC-calcofluor accurate measurements of weight average molar mass (M-w) can be made for beta-glucan populations within 10-500 x 10(3) g/mol. Above this molar mass threshold there is an increasing tendency for underestimation of M-w. Precipitation of some beta-glucan-calcofluor complexes may have delayed their transport into the detector. (C) 2015 Elsevier Ltd. All rights reserved.