DETERMINATION OF ANATOXIN-A AND HOMOANATOXIN IN BLUE-GREEN-ALGAL EXTRACTS BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY AND GAS-CHROMATOGRAPHY MASS-SPECTROMETRY

The production of cyanobacterial toxins as anatoxin-a in the UK by blu e-green algae such as Oscillatoria and Anabaena flos-aquae is a potent ial health hazard, especially to animals, birds and fish. A sensitive reversed-phase ion-pair high-performance liquid chromatographic (RP-HP LC) method is described for the measurement of the neurotoxins anatoxi n-a (AnTx) and homoanatoxin (HomoAnTx) in the presence of lyophilized algal extract. A base-deactivated C18 column material was used with ac etonitrile-phosphate buffer (pH 3) and sodium dodecyl sulfate as ion-p air reagent with ultraviolet detection at 227 nm. Linear calibrations were obtained between 2 and 93 ng on-column for AnTx.HCI and 2-112 ng on-column for HomoAnTx.HCl with limits of detection of 1 and 2 ng on-c olumn, respectively. A sample of Oscillatoria bloom material collected from Loch Insh, Scotland, in 1991 was found by this method to contain approximately 0.8 mg of AnTx.HCI per gram of lyophilized extract. Hom oanatoxin was not present. The identity of AnTx was confirmed by the i solation of the AnTx peak by RP-HPLC, its derivatization to N-butylAnT x and its analysis by RP-HPLC and gas chromatography-mass spectrometry .