Oversulfated chondroitin sulfate, a toxic impurity found in some porcine intestinal heparin samples was separated from intact heparin by capillary electrophoresis using a 600 mM phosphate buffer, pH 3.5 as the background electrolyte in a 56 cm x 25 um id capillary. This method was confirmed in two separate labs, was shown to be linear, reproducible, robust, easy to use and provided higher resolution and superior limits of detection, especially when compared to the official method.  Other glycosoaminoglycans such as dermatan sulfate and heparan sulfate were separated and quantified as well during a single run.  The heparin peak area response correlated well to values obtained using the official assay for biological activity.  An electropherogram obtained via a high speed, high resolution version of the method is shown below.