Validación de una técnica para la determinación de toxinas paralizantes en moluscos bivalvos de Costa Rica mediante cromatografía líquida acoplada a reactor post columna con detector de fluorescencia Validation of a post – column reactor liquid chromatogr

Abstract

Chromatographic and extraction conditions were implemented and validated for the determination of twelve paralytic toxins (PSP) in bivalves, including STX’s (saxitoxins), GTX’s (gonyautoxins) and C’s (N-sulfocarbamoyl gonyautoxins). The extraction method of Rourke et al. [1] was tested and modified using an acid extraction in 0.1 M HCl and 30 m/v trichloroacetic acid in the purification step. The chromatographic methods proposed by Rourke et al. [1] and Franco and Fernández [2] were evaluated. The validation was performed for the first method mentioned [1]; a gradient program is established for the separation of STX’s and GTX’s toxins, and an isocratic method for the separation of C’s. The established method was further validated by determining the correlation coefficient (R) (0.995-1.000), coefficient of determination (R²) (0.989-1.000), linear range (53.7-926.6 μg STX diHCl equivalents/100 g), sensitivity (4.32-60.32 LU (μmol/L)^-1), recovery percentage (58-115%), coefficient of variation (2-17%) for instrumental repeatability and (2-16%) for methodological repeatability, sensitivity (limits of detection (LODs)): 1.1-8.5 μg/100g and limits of quantification (LOQs)): 1.60-12.6 μg/100g. The application of this method proved good performance and capability for simultaneous determination of PSP toxins in bivalve molluscs.