Glucosamine is an amino sugar believed to play a role in cartilage formation and repair. Chondroitin sultate gives cartilage elasticity. Primesep 500 separates glucosamine and chondroitin sulfate with baseline resolution. Chondroitin sulfate is separated from chloride ion by ion exclusion and glucosamine is separated by sodium ion by ion exchange and reversed phase. The HPLC separation uses a mobile phase of water, acetonitrile (MeCN, ACN), and ammonium formate with evaporative light scattering detection (ELSD) with a column temperature of 90C.