Rapid Analysis of Glucosinolates Using Direct-Infusion Mass Spectrometry

We developed a rapid, accurate, and quantitative method for analyzing glucosinolates (GSLs) by combining column-free liquid chromatography (LC) with direct-infusion mass spectrometry (MS). Conventional methods for analyzing GSLs take a long time (20-50 min per sample) to perform compound separation on an LC column. We achieved a shortened analysis time of 30 seconds per sample using a direct-infusion method. Samples were continuously injected by a pump and autosampler on an LC system directly into the MS. Orbitrap MS detected 11 types of GSLs in the extracts of turnip hypocotyls. The calibration curve of a GSL standard showed a linear response over a 6-digit concentration range from 1 nM to 1 mM. In addition, no decrease in the detected intensity of GSL ions in 100 continuous analyses of turnip extracts was observed. This method may be applied for rapid analysis of GSLs and other health-functional or bioactive compounds.