NOTA TÉCNICA - Determination of saxitoxin and its derivatives in mollusk bivalves: Evaluation and optimization of the high performance liquid chromatographic use with fluorescence detection and prior oxidation (Determinación de saxitoxina y sus derivados en moluscos bivalvos: Evaluación y optimización del uso de cromatografía líquida de alta resolución con previa oxidación)

Abstract

Saxitoxin and its derivatives are potent neurotoxins associated with paralytic shellfish poisoning (PSP) in humans which are primarily produced by dinoflagellates. To evaluate and optimize the use of high performance liquid chromatography (HPLC) with previous oxidation in order to determine saxitoxin and its derivatives, samples of the green mussel (Perna viridis   ) and oysters (Crassostrea   sp) were collected at six locations in Venezuela and at four in Trinidad, the latter along the west coast line, in June 2000. The samples were extracted using the AOAC bioassay mouse procedure. Each extract was oxidized using periodic acid and the oxidation product was injected to the chromatographic column. The method used to HPLC in this work was a modification of Lawrence et al. (1996). The separation of important pairs of toxins (STX/NEO, GTX1,4/GTX2,3) were achieved, but the resolution and height of the peaks of oxidation products of these toxins varied depending on column efficiencies. Some samples had presence of PSP below permissible levels, which was confirmed by using bioassay mouse method. The results showed that the reaction precolumn method gives prompt information about profile of the toxins, which is independent of matrix of receptor organism, and it is a simple method for monitoring PSP in shellfish in the Caribbean