ANALYSIS OF THIAMINE IN DRIED YEAST BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY AND HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY ATMOSPHERIC-PRESSURE CHEMICAL-IONIZATION MASS-SPECTROMETRY

High-performance liquid chromatography (HPLC) and high-performance liq uid chromatography/atmospheric pressure chemical ionization-mass spect rometry (HPLC/APCI-MS) have been applied to the analysis of thiamine i n dried yeast. Thiamine was extracted from dried yeast with isobutanol containing sodium 1-octanesulfonate as an ion-pairing agent and deter mined by HPLC on a reversed phase ODS column with UV detection at 254 nm. Response was linear in the range 25-300 mug/g of thiamine in dried yeast with a coefficient of variation in the reproducibility of 8.0 % . Thiamine was recovered in good yield (109.2 %, n = 5). Identificatio n of the thiamine peak was obtained by the mass spectrum using the HPL C/APCI-MS system. The utility of the selected ion monitoring technique using the HPLC/APCI-MS was also investigated. The results obtained by this method are in good agreement with those obtained by the thiochro me method [1].