... Supplies, Poole, Dorset, UK) mM 2-sulfo-N-acetylglucosamine, 3-sulfo-N-acetylglucosamine, and 6-sulfo-Nacetylglucosamine, in water (see Note 3) 2.2 Equipment High-performance liquid chromatography ... after h of hydrolysis (linkage lability: 6- > 2- > 3-) , we recommend including two external controls that contain an equimolar mixture of 2-, 3- and 6-sulfo-N-acetylglucosamine in water: a nmol control ... be thoroughly dried before weighing and making up as standards Standards of mM each of 2-, 3-, and 6-sulfo-Nacetylglucosamine in water may be aliquoted and stored at –20°C, and used as required...