Rapid determination of microcystins and nodularin in surface water by on-line solid-phase extraction (SPE) with ultra-performance liquid chromatography – tandem mass spectrometry (UPLC-MS/MS)

Abstract

A method for determining seven microcystins and nodularin in surface water at nanogram per liter concentrations was developed based on on-line solid-phase extraction ultra-performance liquid chromatography – electrospray ionization tandem mass spectrometry (on-line SPE-UPLC-MS/MS). Aliquots of 5 mL water sample were directly injected into on-line SPE after passage through a membrane filter. The water sample was enriched and purified by a hydrophilic–liphophilic balance (HLB) polymeric column and eluted by mobile phase. The analytes were separated by Acquity BEH130 column, detected using tandem mass spectrometry, and quantified by external standardization. Under the optimized conditions, the method detection limits for all of the targets ranged from 1.4 to 3.3 ng/L with the recoveries from 85.5 to 121%. The precision of the method, indicated by the relative standard deviation, was 3.87 to 13.9%. The results of the analysis of surface water samples demonstrated that the proposed method has the ability to determine microcystins and nodularin without the need for complex manual pretreatment.