DEVELOPMENT AND VALIDATION OF AN SPE-LC-MS/MS METHOD FOR THE SIMULTANEOUS DETERMINATION OF MULTICLASS CYANOTOXINS IN WATER

摘要

Cyanobacteria are present in surface waters and under favorable environmental conditions can form extensive algal blooms and release hazardous toxic compounds (cyanotoxins), posing a significant risk to aquatic habitats and human health. Cyanotoxins comprise a large group of organic compounds, with a variety of physicochemical properties, chemical structures (alkaloids, cyclic peptides, amino acids, lipopolysaccharides etc) and toxic activity (hepatotoxic, neurotoxic, cytotoxic, dermatotoxic). In this study, we present the development and optimization of a fast and sensitive analytical method for the preconcentration and simultaneous determination of multi-class cyanotoxins in water.The targeted compounds were: Cylindrospermopsin, Anatoxin-a, Nodularin and 12 Microcystins ([D-Asp3]MC-RR, MC-RR, MC-YR, MC-HtyR, [D-Asp3]MC-LR, MC-LR, MC-HilR, MC-WR, MC-LA, MC-LY, MC-LW and MC-LF). For the chromatographic separation of the compounds a reversed phase column was used (Atlantis T3, 100x2.1 mm, 3um, Waters). A gradient elution program was used with mobile phase acetonitrile (A) 5-100% and (B) water, both containing 0.5% formic acid, at a flow rate of 0.2 mL.min-1, resulting in analysis time of 43 min. Ionization was positive ESI in multiple SRM mode. Solid Phase Extraction included two tandem SPE cartridges, Oasis HLB (200mg, 6cc, Waters) and porous graphitic carbon (Hyper PGC, 200mg, Thermo) for efficient extraction of the target toxins from water. SPE factors studied were the proportion of methanol - dichloromethane, the presence of formic acid in the elution solvent and the volume of elution solvent.Based on the obtained results, the use of mixed SPE sorbents enhances the overall efficiency of the method for most of the compounds. Mean recoveries ranged 71.4% to 94.5% except for Anatoxin-a, MC-WR, MC-LW and MC-LF which were slightly reduced. Repeatability and reproducibility of the method was satisfying.