Dados do Trabalho

Título

A NEW METHOD FOR THE ANALYSIS OF PARALYTIC TOXINS IN OYSTERS AND MUSSELS

Introdução

The consumption of bivalve mollusks such as oysters and mussels has grown sustainably worldwide. In Brazil, by 2022, over 90% of production was concentrated in the state of Santa Catarina. Recently, other regions have started to produce oysters and mussels commercially. However, the consumption of these foods can present significant toxicological risks mainly due to marine toxins. Being filter feeders, bivalve mollusks can accumulate toxins in their tissues, requiring constant analytical laboratory monitoring. One of the most complex groups of toxins to analyze is the paralytic toxins (PSP), with saxitoxin being particularly notable. The official control method (AOAC and European Community) is complex, difficult to execute and interpret. Samples are extracted with 1% acetic acid, purified by two stages of solid phase extraction, and oxidized with periodic acid and hydrogen peroxide in parallel, resulting in different extracts analyzed by HPLC with fluorescence detection. This method presents the problem of co-elution of analytes, which can lead to interpretative errors.

Material e Métodos

This work presents an alternative method that is faster and more efficient in the separation and identification of marine toxins. It uses extraction with 1% acetic acid followed by simple filtration with a nylon membrane (0.22 µm) and direct injection into an LC-MS/MS system using separation on a dual column system (C4 and C18). Preliminary results were tested with samples fortified with two representative toxins of the paralytic chemical groups: neosaxitoxin and decarbamoyl-neosaxitoxin. Fortified samples (2 g) of mussel and oyster were extracted with two aliquots of 2 mL of 1% acetic acid. The extracts were heated to 100 °C for 5 minutes, centrifuged, and filtered before analysis.

Resultados e Discussão

The results indicate that the proposed new method allows for faster and more specific analysis without the need for additional oxidations. The separation of PSP toxins on the C4 column was effective, also allowing the simultaneous analysis of diarrhetic (DSP) and amnesic toxins (ASP) by sequential extraction with methanol followed by hot acetic acid. The reverse order of extraction was also evaluated with promising results.

Conclusão

This method is under validation for application in regulatory monitoring of these toxins in bivalve mollusks.