Determination of microcystins in blue-green algae, fish and water using liquid chromatography with ultraviolet detection after sample clean-up employing immunoaffinity chromatography.
Anti-microcystin LR immunnoaffinity cartridges were evaluated for their ability to selectively remove microcystins from extracts of blue-green algae, fish and water samples for subsequent analysis by liquid chromatography with UV absorbance detection at 238 nm. Blue-green algae and fish samples were extracted with 75% methanol in water. A portion of the extract was diluted and passed through an immunoaffinity cartridge. Water samples were applied directly to the cartridge. The cartridge was rinsed with water and 25% methanol in water. The microcystins were eluted with 80% methanol in water containing 4% acetic acid. It was found that the cartridges were effective in isolating the microcystins from blue-green algae, fish and water samples, resulting in extracts that were clean enough to enable direct LC-UV detection down to approximately 0.03 microg/g in the blue-green algae and fish samples, and as low as 0.02 ng/ml for water samples. The cartridges were found to have a capacity of approximately 200 ng each for a mixture of microcystins RR, YR, LR and LA, or as much as 525-800 ng for individual compounds. Recoveries trough the complete analytical procedure ranged from 64 to 115% (all values) with an overall average of approximately 80% at spiking levels of 0.5-4.0 microg/g for the microcystins in blue-green algae. The average recoveries (n=8) from spiked (0.1-0.5 microg/g) fish samples were 73% for RR, 79% for YR, 81% for LR and 77% for LA, while from the spiked (2.0-0.04 ng/g) tap and river water samples (n=6), recoveries were 78% for RR, 86% for YR, 94% for LR and 89% for LA.
Lawrence
J F
JF
Food Research Division, Bureau of Chemical Safety, Banting Research Centre, Health Canada, Ottawa, Ont., Canada. jim_lawrence@hc-sc.gc.ca
Menard
C
C
D000818:Animals; D002846:Chromatography, Affinity / Q000379:methods*; D000458:Cyanobacteria / Q000737:chemistry*; D005399:Fishes; D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic / Q000032:analysis*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*; D014867:Water / Q000737:chemistry*
D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic; D014867:Water; C057862:cyanoginosin LR