HPLC-HRMS method for fast phytochelatins determination in plants. Application to analysis of Clinopodium vulgare L.

An optimized analytical method based on C8 core-shell reverse phase chromatographic separation and high resolution mass spectral (HRMS) detection is developed for a fast analysis of unbound phytochelatins (PCs) in plants. Its application to analysis of Clinopodium vulgare L. is demonstrated where proper PCs liberating and preservation conditions were employed using dithiotreitol in the extraction step. A baseline separation of glutathione (GSH) and phytochelatins from 2 to 5 (PC2-PC5) for 3 min was achieved at conventional HPLC backpressure, with detection limits from 3 ppt (for GSH) to 2.5 ppb (for PC5). It is shown, that the use of HRMS with tandem mass spectral (MS/MS) capabilities permits additional wide range screening ability for iso-phytochelatins and PC similar compounds, based on exact mass and fragment spectra in a post acquisition manner.