Simultaneous rapid determination of 12 microcystins and one nodularin in water by direct injection-ultra performance liquid chromatography-triple quadrupole mass spectrometry

Abstract

A rapid method was developed for the simultaneous determination of 12 microcystins (MCs) and one nodularin (NOD) in water by direct injection-ultra performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS/MS). The water samples were first diluted with equal volume of methanol, and then filtered through polyether sulfone (PES) syringe filter. The filtrates were directly injected into the UPLC system. The separation of the analytes was carried out on an ACQUITY UPLC BEH 300 C18 column (100 mm×2.1 mm, 1.7 μm) with gradient elution using mobile phases of acetonitrile containing 0.1% (v/v) formic acid and 0.2% (v/v) formic acid aqueous solution. The 12 microcystins and one nodularin were detected by positive electrospray ionization in the multiple reaction monitoring (MRM) mode, and quantified by standard solvent external standard method. The limits of detection were 0.03-0.1 μg/L and the limits of quantification were 0.1-0.3 μg/L. The recoveries were in the range of 79.5%-123% with the relative standard deviations ranging from 1.0% to 20% (n=6). The method is simple, sensitive and accurate, and has been successfully applied to the detection of the 13 kinds of algae toxins in water.