Identification and quantification of uronic acid-containing polysaccharides in tissues of Russian sturgeon (Acipenser gueldenstaedtii) by HPLC–MS/MS and HPLC–MSn

Uronic acid-containing polysaccharides (UACPs) including glycosaminoglycans (GAGs) and some non-GAGs in different tissues of Russian sturgeon were analyzed by detecting characteristic oligosaccharides in their acid hydrolysates after 1-phenyl-3-methyl-5-pyrazolone (PMP) derivatization. Disaccharides without substituents were identified and quantified using HPLC–MS/MS with a triple quadrupole mass spectrometer, while other oligosaccharides including sulfated/acetylated disaccharides and tetrasaccharides were characterized by HPLC–MSn with a linear ion trap mass spectrometer. The results showed that the nostril, gill arch and notochord of Russian sturgeon contained high amounts of CS ranging from 1700 to 3660 mg per 100 g of dried tissues. A non-GAG UACP, named AGSP, with a backbone of →4)-GlcA(1 → 2)-Man(1→, was found in the gill arch, caudal fin and notochord of sturgeon with the contents from 37 to 227 mg per 100 g of dried tissue. Another two unknown non-GAGs, UP1 and UP2, existed in intestine and in body muscles and gill arch, respectively. And an unidentified GAG (UP3) was found in testes, ovaries, swim bladder, intestine and skin. This investigation was the first effort to determine the overall UACP species in sturgeon after extraction of the eggs and caviar production.