title: Determination of microcystins in cyanobacterial blooms by solid-phase microextraction-high-performance liquid chromatography.
abstract: A solid-phase microextraction (SPME) method was applied to study microcystin (MC) profiles in a natural Microcystis sp. bloom in a freshwater pond in Guangzhou, China. Three dominant MC variants, namely MC-LR, MC-YR, and MC-RR, were quantified. Simultaneous study of their total, extracellular, and intracellular profiles was made possible using SPME coupled to high-performance liquid chromatography. The total and intracellular concentrations of MC-LR in the bloom were 8.67 x 10(-2) microg/ ml and 1.93 mg/g, respectively. The corresponding concentrations of MC-YR were 1.20 x 10(-3) microg/ml and 0.06 mg/g, respectively, and those of MC-RR were 5.57 x 10(-2) microg/ml and 1.49 mg/g, respectively. Only MC-LR was detectable in the extracellular phase (1.49 x 10(-2) microg/ml) of the bloom, and its concentration was 14% of the intracellular content. Mass balance consideration revealed that only 71.1% of total MC-LR, 36.0% of total MC-YR, and 67.4% of total MC-RR within the cyanobacterial cells were released into the aqueous phase immediately after cell lysis.
authors.affiliation: Centre for Coastal Pollution and Conservation, Department of Biology and Chemistry, City University of Hong Kong, Hong Kong SAR, China.
authors.forename: K F
authors.initials: KF
authors.lastname: Poon
authors.forename: M H
authors.initials: MH
authors.lastname: Lam
authors.forename: P K
authors.initials: PK
authors.lastname: Lam
authors.forename: B S
authors.initials: BS
authors.lastname: Wong
mesh_terms: D002851:Chromatography, High Pressure Liquid; D000458:Cyanobacteria; D004784:Environmental Monitoring / Q000379:methods; D005068:Eutrophication; D007424:Intracellular Fluid / Q000737:chemistry; D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic / Q000032:analysis*
chemical_list: D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic; C065685:microcystin YR; C063855:microcystin RR; C057862:cyanoginosin LR