Determination of anatoxin-a and homoanatoxin in blue-green algal extracts by high-performance liquid chromatography and gas chromatography-mass spectrometry

• Published in: Analyst (London) 1993, Vol.118 (7), p.753-758
• Main Authors: ZOTOU, A, JEFFERIES, T. M, BROUGH, P. A, GALLAGHER, T
• Format: Article
• Language: English
• Subjects: Bacteriology; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Microbiology; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains
• ISSN: 0003-2654; 1364-5528
• DOI: 10.1039/AN9931800753

A sensitive reversed-phase ion-pair high performance liquid chromatography (RP-HPLC) method was developed to measure neurotoxins in algal extracts. Anatoxin-a (AnTx) and homoanatoxin (HomoAnTx) were synthesized as hydrochlorides to calibrate the method. The RP-HPLC method used a base-deactivated C18 column material with acetonitrile-phosphate buffer at pH 3, sodium dodecyl sulphate as ion-pair reagent, and UV detection at 227 nm. Lyophilized algal material was extracted with acetonitrile and injected in 50 ul aliquots on to the RP-HPLC column to separate the neurotoxins from other algal components. The chromotographed material was collected and dissolved in ethanol for subsequent quantitative analysis. N-butyl derivatives were also prepared for both RP-HPLC and gas chromatography-mass spectrometry. Linear calibrations were obtained in the ranges 2-93 and 2-112 ng of AnTx and HomoAnTx, respectively; detection limits were 1-2 ng. An Oscillatoria bloom on Insh loch in 1991 contained 0.8 mg AnTx per g of lyophilized extract and no HomoAnTx.