Screening for cyanobacterial hepatotoxins, microcystins and nodularin in environmental water samples by reversed-phase liquid chromatography-electrospray ionisation mass spectrometry.
Water samples taken from 93 freshwater and brackish water locations in Aland (SW Finland) in 2001 were analysed for biomass-bound microcystins and nodularin, cyanobacterial peptide hepatotoxins, by liquid chromatography-mass spectrometry (LC-MS) in selected ion recording (SIR) and multiple reaction monitoring modes, HPLC-UV, and enzyme-linked immunosorbent assay (ELISA). The extracted toxins were separated on a short C18 column with a gradient of acetonitrile and 0.5% formic acid, and quantified on a Micromass Quattro Micro triple-quadrupole mass spectrometer with an electrospray ion source operated in the positive SIR or scan mode. An injection of 50 pg of microcystin-LR, m/z 995.5, on column gave a signal-to-noise ratio of 17 (peak-to-peak) at the chosen SIR conditions. In-source or MS-MS fragmentation to m/z 135.1, a fragment common to most microcystins and nodularin, was used for confirmatory purposes. Microcystins with a total toxin concentration equal to or higher than 0.2 microg l(-1) were confirmed by all three methods in water samples from 14 locations. The highest toxin concentration in a water sample was 42 microg l(-1). The most common toxins found were microcystins RR, LR and YR with different degrees of demethylation (non-, mono- or didemethylated). Parallel results achieved with ELISA and HPLC-UV were generally in good agreement with the LC-MS SIR results.
Spoof
Lisa
L
Department of Biochemistry and Pharmacy, Abo Akademi University, P.O. Box 66, 20521 Turku, Finland.
Vesterkvist
Pia
P
Lindholm
Tore
T
Meriluoto
Jussi
J
D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D000458:Cyanobacteria / Q000737:chemistry*; D004797:Enzyme-Linked Immunosorbent Assay; D008099:Liver / Q000187:drug effects*; D052998:Microcystins; D010456:Peptides, Cyclic / Q000032:analysis* / Q000633:toxicity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013056:Spectrophotometry, Ultraviolet; D014874:Water Pollutants, Chemical / Q000032:analysis*
D052998:Microcystins; D010456:Peptides, Cyclic; D014874:Water Pollutants, Chemical; C063998:nodularin; C078588:microcystin