Determination of betaine in Lycium chinense fruits by liquid chromatography-electrospray ionization mass spectrometry

A rapid and sensitive high-performance liquid chromatography-electrospray m ass spectrometric method has been developed for the determination of betain e in Lycium chinense fruits. Betaine was analyzed on a system consisting of a NH2 stationary phase and a mobile phase of water-acetonitrile (25:75) by isocratic elution for 40 min. Betaine was identified and quantitated by el ectrospray ionization mass spectrometry with selected ion monitoring of the protonated ion [Betaine+H](+) and clustered ions [nBetaines+H](+). The lim it of detection for betaine by this method was ca. 0.2 ng/ml and the relati ve standard deviations of the assay (intra- and inter-day) were less than 8 .1%. (C) 1999 Elsevier Science B.V. All rights reserved.