Application of Thermospray Liquid Chromatography /Mass Spectrometry to the Analysis of Water-Soluble Vitamins

Thermospray liquid chromatography/mass spectrometry with a new, strongly acidic mobile phase, i.e. , formic acid-ammonium formate buffer system, was applied to the analysis of five kinds of water-soluble vitamins. Their detection limits, linearity and reproducibilities were examined. The mass spectra of the individual vitamins gave MH* ions; some of these showed fragment ions giving information on molecular structure. Detection limits ( S / N >10) were 10–100 pg; reproducibility of 1.2–4.9% (RSD) was obtained for 10 μl syringe injections, based on peak areas. The water-soluble vitamins in a commercial health drink and in fermented soybean paste miso were determined by this method.