The heparin hexasaccharide MS standard 6 has been purified as one defined sequence and structure. It is not a mix of oligosaccharides. It is a heparin hexasaccharide with six sulfates attached to a repeating structure of α(1-4) linked Uronic Acid (UA) β(1-4) linked to N-Acetylglucosamine (GlcNAc) or N-sulfylglucosamine (GlcNS). The exact structure of the heparin hexasaccharide MS standard 6 is ∆UA2S - GlcNS6S -UA- GlcNAc6S-IdoA - GlcNS6S. The uronic acid residue may be either glucuronic or iduronic acid. It has an exact mass of 1533.05.