1999 Volume 125 Issue 1 Pages 160-165
This paper describes a new HPLC method for the sugar analysis of algal galactans containing 3, 6-anhydrogalactose, which is readily destroyed during usual acid hydrolysis and methanolysis. By anhydrous mercaptolysis of galactans at 60°C for 6 h with the newly developed solvent system, 0.5 N HCl/[ethanethiol:methanol (2:1, v/v)], component sugars, including 3, 6-anhydrogalactose, were liberated quantitatively as their diethyl dithioacetals. The resultant sugar diethyl dithioacetals were found to have strong UV-absorption (absorption maximum of 3, 6-anhydrogalactose diethyl dithioacetal in water, 191-192 nm; molar extinction coefficient, 4, 400). The sugar diethyl dithioacetals were then resolved simultaneously within 15min by reversed phase HPLC with 30% acetonitrile as the eluent and detected by UV-absorption at 215 nm. Amounts of sugar diethyl dithioacetals less than 50 pmol can be determined without further derivatization.
