Gel permeation chromatography with interference refractometry for the rapid assay of polydisperse dextrans in...

A semi-automatic system incorporating an ultra-sensitive interference refractometer coupled to a dual-column gel permeation apparatus has been devised for measurement of the molecular size distribution of dextrans in small samples of serum and urine. The system was calibrated with seventeen defined dextran fractions with a range of 1200-250,000 weight average molecular weight (Mw). Urine samples were prepared for analysis by passage through small ion-exchange columns; serum was pretreated by precipitation with trichloroacetic acid and centrifuged before the ion-exchange treatment. Internal standard (dextran, 2 X 10(6) Mw) was added to each sample before pretreatment. Data were obtained in a form suitable for computerised analysis.