Application of Hydrophilic Interaction Liquid Chromatography Combined with Positive and Negative Ionization Mass Spectrometry for the Analysis of PSP Toxins

Abstract

Hydrophilic interaction chromatography (HILIC) is a useful technique for the separation of PSP toxins that offers a good selectivity and increases the sensitivity of their detection by mass spectrometry (MS/MS). In this study the analytical conditions of the separation and detection were optimized by testing the effect of some components as column, the organic modifier (type and percentage)in the mobile phase, pH, buffer character and concentration and flow rate. Both types of ionization (positive and negative) were used in the same run. The best results were obtained with a ZIC-HILIC (Merck), using a gradient elution, detecting the toxins in negative ionization mode during the first part of the chromatogram, and in positive mode during the final part. The limits of detection (LODs) and quantization (LOQs) obtained were acceptable for all toxins and low enough for routine monitoring, as well of the analysis time. The matrix effects were observed for some PSP toxins in mussel extracts, so a simple solid phase extraction (SPE) method to clean up the extracts prior the analysis was developed;