Mcs mc lr

Water, acetonitrile, methanol, and formic acid were all Optima LC/MS grade solvents and purchased from Fisher Scientific (Tewksbury, MA, USA). MCs MC-LR, RR, YR, WR, HtyR, HilR, D-Asp³-RR, D-Asp³-LR, LA, LF, LY, LW, and Nodularin were purchased from Enzo Life Sciences, Inc. (Farmingdale, NY, USA). The surrogate C₂D₅ MC-LR was purchased from Cambridge Isotope Laboratories, Inc. (Tewksbury, MA, USA). The Microcystin-Adda ELISA kit was purchased from Abraxis, Inc. (Warminster, PA, USA).
Standards were prepared in methanol and diluted to ng/L concentrations in LC MS grade water. All water samples were collected according to US EPA method 546: Determination of Total Microcystins and Nodularins in Drinking Water and Ambient Water by Adda Enzyme-Linked Immunosorbent Assay. Briefly, for ambient waters, EPA Method 546 does not require any preservatives to be added to the sample collection containers [12 ]. A 40 mL lake water sample was collected in PETG bottle at approximately 30 cm below the surface of the water. Samples were stored on ice after collection and until arrival to the lab where they were then frozen at −8 °C. MCs were released from the cells by subjecting the samples to a series of three freeze thaw cycles and debris was removed by filtering through a 1 µm glass fiber filter [18 (link),21 (link),23 (link)].

Water, acetonitrile, methanol, acetic acid, and formic acid were all Optima LC–MS grade solvents purchased from Fisher Scientific (Tewksbury, MA, USA). Additionally, 2-mercaptoethanol was purchased from Sigma Aldrich (St. Louis, MO, USA). MCs MC-LR, RR, YR, WR, HtyR, HilR, [d-Asp³]-RR, [d-Asp³]-LR, LA, LF, LY, and LW, as well as nodularin, were purchased from Enzo Life Sciences, Inc. (Farmingdale, NY, USA). The surrogate C₂D₅ MC-LR was purchased from Cambridge Isotope Laboratories, Inc. (Tewksbury, MA, USA). The Microcystins-Adda ELISA kit was purchased from Abraxis, Inc. (Warminster, PA, USA). Standards were prepared in methanol and diluted in LC–MS grade water. Samples were stored on ice after collection and until arrival to the laboratory where they were then frozen at −4 °C. Samples then went through a series of three freeze–thaw cycles before analysis [31 (link),39 (link),40 (link)].