Absolute Molecular Weight Distribution of Low-Molecular-Weight Heparins by Size-Exclusion Chromatography with Multiangle Laser Light Scattering Detection

The absolute molecular weight (Mr) distribution of seven low-molecular-weight (LMW) heparin products was determined by size-exclusion chromatography (SEC) coupled with multiangle laser light scattering (MALLS) detection. The SEC/MALLS technique does not rely on relativeMrstandards for column calibration and yields absoluteMrestimates directly from the angular dependence of scattered light intensity as a function of concentration, as formulated by light scattering theory. The SEC/MALLS method we describe is rapid, precise, and accurate. In 1 h it yields results from triplicate injections that agree well with the manufacturers’ own independent analyses and that exhibit coefficients of variation of ∼1%. By eliminating the requirement for finite quantities of highly purified, well-characterizedMrstandards derived from heparin, the present procedure represents a clear improvement over relative methods ofMrdetermination. Thus, it is concluded that the SEC/MALLS method is ideally suited to routine quality control of commercial LMW-heparin products.