Use of an Evaporative Light Scattering Detector Coupled to MALLS for Determination of Polysaccharide Molecular Weights

Abstract

A method to calibrate and use an evaporative light scattering detector (ELS) as a mass detector for molecular weight determination of polysaccharides using a multi-angle laser light scattering detector (MALLS) is described. The calibration of the ELS is performed under isocratic conditions using concentration values obtained from an interferometric refractive index detector (RI). The observed response fit a power trendline (y ¼ ax b ) for the concentration response of the RI versus the voltage response of the ELS. The combined average log a coefficient was (5.472, s.d. ¼ 0.020) and the average b coefficient was (1.372, s.d. ¼ 0.004) for all the runs. Band broadening, which could occur between the detectors, was not observed and did not affect the calibration values. Without adjustment the ELS was used as a mass detector for MALLS to accurately determine molecular weights (MW) at elevated buffer concentrations.

Pectin homogalacturonans: Nanostructural characterization of methylesterified domains

“…DM and MW analysis have been described in detail previously (Luzio, 2006;Luzio & Cameron, 2010). Briefly, the SEC system consisted of a pump (Model 1000D syringe pump, ISCO, Lincoln, Nebraska) and an inline filter (0.02 mm pore size, Anodisc 25; Whatman, Maidstone, UK).…”

Determination of degree of methylation of food pectins by chromatography

“…Methods of detection have been used in combination with liquid chromatography for characterisation of pectin DM by measurement of MeOH by HPLC, but such methods still rely on a separate measurement of GalA by a colorimetric acid procedure . Colorimetric assays for GalA may be less accurate if neutral sugars, alcohols and other interfering impurities are present …”