Extraction and high-performance liquid chromatographic method for the determination of microcystins in raw and treated waters

Abstract

Increasing concern over the presence of microcystins (cyanobacterial/blue-green algal hepatotoxins) in water supplies has emphasized the need for a suitable analytical method. As many microcystins are known to exist, a method was developed that permits the determination of numerous variants by a single procedure. The method involves filtration to separate cyanobacterial cells from water, allowing intracellular and extracellular toxin levels to be assessed. The cellular components of the samples are extracted repeatedly in methanol, which was found to be the most versatile solvent tested for the extraction of microcystins. The efficiency of this extraction procedure was found to be independent of cell biomass. The filtered water was subjected to trace enrichment using a C18 solid-phase extraction cartridge, followed by identification and determination by photodiode-array high-performance liquid chromatography. The procedure was assessed using four water samples (two raw and two treated) spiked with a mixture of five microcystins and the cyanobacterial hepatotoxin nodularin. Recoveries of all but one microcystin were found to be good when spiked with concentrations as low as 250 ng l-1. The linearity and precision of the experimental procedure were assessed for five microcystins and nodularin. The proposed method permits rapid sample processing and determination of several microcystins.

Sorption, degradation and mobility of microcystins in Chinese agriculture soils: risk assessment for groundwater protection

“…HPLC was employed to determine the concentrations of microcystins in extracted solutions (Chen et al, 2005;Lawton et al, 1994). Briefly, The Shimadzu LC-10A system included two LC-10A pumps and a UV detector.…”

Optimization of an effective extraction procedure for the analysis of microcystins in soils and lake sediments

“…Total flow was 1 ml/min. Column temperature was maintained at 40 C and injection volume was 10 ml (Lawton et al, 1994;Chen et al, 2004). …”

Rapid quantification of total microcystins in cyanobacterial samples by periodate-permanganate oxidation and reversed-phase liquid chromatography

“…Biochemical methods such as enzyme-linked immunosorbent assay (ELISA) [18][19][20] and the protein phosphatase inhibition assay [5,21] are useful as screening methods due to their high sensitivity and high throughput, but they often have poor identification ability and the potential for false-positives. Reversedphase high-performance liquid chromatography (HPLC) with UV detection [20], diode array detection [22][23][24][25][26][27] or electrochemical detection [28], LC-mass spectrometry (LC-MS) [29][30][31], capillary electrophoresis (CE) [30], and CE-MS [30] have also been used for the identification and quantification of MCs. The LC method can be much more definitive than bioassays and biochemical methods 0003 since it can provide information for the identification of individual MCs.…”