Development and application of ultra performance liquid chromatography-electrospray ionization tandem triple quadrupole mass spectrometry for determination of seven microcystins in water samples

In the present work, an ultra performance liquid chromatography (UPLC)-electrospray ionization tandem triple quadrupole/mass spectrometry (ESI-MS/MS) method was developed in selected reaction monitoring (SRM) mode to determine the amounts of seven/microcystin variants (MCYST-RR, -YR, -LR, -LA, -LY, -LW, -LF) in water samples. Solid phase extraction (SPE) or porous filter was used for sample cleaning-up and analyte enrichment. A C18 column enabled separation of 7 microcystins within 10 min. Translation reaction ions including 995.6 > 134.9 (RR), 1045.8 > 135.1 (YR), 910.9 > 375.7 (LA), 1002.3 > 375.6 (LY), 520.1 > 135.0 (LR), 1025.8 > 891.7 (LW), 986.8 > 852.6 (LF) were set as quantitative ions and the enkephalin was the internal standard. Upon method validation, the limits of detection (LODs) and limits of quantification (LOQs) were found to be 0.06 μg L−1 and 0.2 μg L−1 (injection volume of 10 μL), respectively, for all seven microcystin variants. The correlation coefficients were larger than 0.994 in all linear ranges and recoveries were in the range of 66.24-99.22%. The developed approach was highly sensitive and easy to perform. It generated accurate quantitative results for the analysis of microcystins in environmental water samples with a wide concentration range. The results showed that MC-RR and MC-LR widely existed in polluted water, while MC-LA and MC-LY were detected sporadically.