Determination of vitamin B1 in seawater and microalgal fermentation media by high-performance liquid chromatography with fluorescence detection

A highly sensitive high-performance liquid chromatographic method with fluorescence detection has been developed for determination of vitamin B(1). Vitamin B(1) was converted into a fluorescent compound by treatment with hydrogen peroxide-horseradish peroxidase and the derivative was subsequently analyzed by HPLC on a Waters Spherisorb ODS2 column (250 mm x 4.6 mm ID, 5 microm) with 40:60 methanol-pH 8.5 acetate buffer solution as mobile phase and fluorescence detection at 440 nm (with excitation at 375 nm). The calibration graph was linear from 5.00 x 10(-10) mol L(-1) to 5.00 x 10(-7) mol L(-1) for vitamin B1 with a correlation coefficient of 0.9991 (n = 9). The detection limit was 1.0 x 10(-10) mol L(-1). The method was successfully used for determination of vitamin B1 at pg mL(-1) levels in microalgal fermentation media and seawater after solid-phase extraction. Recovery was from 89 to 110% and the relative standard deviation was in the range 1.1 to 4.3%.