DETERMINATION OF SUGARS IN UNCONCENTRATED SEAWATER AND OTHER NATURAL-WATERS BY LIQUID-CHROMATOGRAPHY AND PULSED AMPEROMETRIC DETECTION

Reducing and nonreducing sugars, including sugar alcohols, were determined in seawater and other natural waters without preconcentration steps required in past studies. Sugars were separated by anion-exchange chromatography at pH > 11 followed by detection by triple-pulsed amperometry. Prior to injection, seawater samples were rapidly desalted either by use of a mixed bed of anion- and cation-exchange resins in carbonate and hydrogen forms, respectively, or by use of cation-exchange resin in silver form, to remove chloride, followed by precipitation of sulfate as the barium salt. Concentrations of individual sugars in seawater samples were usually < 50 nM. The relative standard deviation was 5-10% at this level. Detection limits for mono- and disaccharides in unconcentrated natural water samples ranged from 2 to 10 nM with a signal-to-noise ratio of 3.