(a) Sugar standard solution.-Dry individual sugar standards (fructose, glucose, sucrose, and maltose; available from Sigma Chemical Co.) 12h at 600C under vacuum. Dissolve in alcohol-H2O (1+1) to obtain concentrations of 3 mg/mL each for fructose, glucose, and maltose and 15 mg/mL for sucrose. After LC injection, compare peak response of test portion and standard, and adjust concentrations of standard solution proportionately to obtain standard response within 10% of test portion responses.