Polymeric ion exchange material based dispersive micro solid-phase extraction of lipophilic marine toxins in seawater followed by the Q Exactive mass spectrometer analysis using a scheduled high resolution parallel reaction monitoring

In recent years, harmful algal blooms have been occurring frequently all over the world, which caused a great negative impact on marine ecosystem, aquaculture and human health. Lipophilic marine toxins (LMTs) produced by certain harmful alga are closely related to diarrheic shellfish poisoning. In this study, a new sample preparation method was established by performing dispersive micro solid-phase extraction (DMSPE) procedure using mixed polymeric ion exchange material as the adsorbent for the simultaneous extraction of LMTs in seawater. To obtain the optimal extraction efficiency of LMTs, the key factors including the type and the amount of adsorbent, the type and volume of eluent, and the concentration of sodium chloride were investigated in detail. A good enrichment effect and weak matrix effects were observed after the DMSPE procedure. Compared with conventional solid-phase extraction sample preparation, the advantages of DMSPE procedure were present in convenience and low cost. In high resolution mass spectrometry (HRMS) detection, a new scheduled high resolution parallel reaction monitoring (PRM) mode was selected for qualitative and quantitative analysis to improve the selectivity and sensitivity of LMTs in seawater. Based on an effective combination of DMSPE procedure in sample preparation and high resolution PRM in data acquisition, a sufficiently low detection level (pg/L level) was achieved for the routine monitoring of LMTs in seawater.