title: Determination of Gonyautoxin-4 in Echinoderms and Gastropod Matrices by Conversion to Neosaxitoxin Using 2-Mercaptoethanol and Post-Column Oxidation Liquid Chromatography with Fluorescence Detection.
abstract: Paralytic Shellfish Toxin blooms are common worldwide, which makes their monitoring crucial in the prevention of poisoning incidents. These toxins can be monitored by a variety of techniques, including mouse bioassay, receptor binding assay, and liquid chromatography with either mass spectrometric or pre- or post-column fluorescence detection. The post-column oxidation liquid chromatography with fluorescence detection method, used routinely in our laboratory, has been shown to be a reliable method for monitoring paralytic shellfish toxins in mussel, scallop, oyster and clam species. However, due to its high sensitivity to naturally fluorescent matrix interferences, when working with unconventional matrices, there may be problems in identifying toxins because of naturally fluorescent interferences that co-elute with the toxin peaks. This can lead to erroneous identification. In this study, in order to overcome this challenge in echinoderm and gastropod matrices, we optimized the conversion of Gonyautoxins 1 and 4 to Neosaxitoxin with 2-mercaptoethanol. We present a new and less time-consuming method with a good recovery (82.2%, RSD 1.1%, n = 3), requiring only a single reaction step.
authors.affiliation: Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre, Porto 4619-007, Portugal. marisasilva17@gmail.com.|Interdisciplinary Center of Marine and Environmental Research-CIMAR/CIIMAR, University of Porto, Rua dos Bragas, 289, Porto 4050-123, Portugal. marisasilva17@gmail.com.
authors.forename: Marisa
authors.initials: M
authors.lastname: Silva
authors.affiliation: Department of Analytical Chemistry, Science Faculty, University of Santiago of Compostela, Lugo 27002, Spain. veronica.rey@rai.usc.es.
authors.forename: Verónica
authors.initials: V
authors.lastname: Rey
authors.affiliation: Department of Analytical Chemistry, Science Faculty, University of Santiago of Compostela, Lugo 27002, Spain. anamaria.botana@usc.es.
authors.forename: Ana
authors.initials: A
authors.lastname: Botana
authors.affiliation: Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre, Porto 4619-007, Portugal. vmvascon@fc.up.pt.|Interdisciplinary Center of Marine and Environmental Research-CIMAR/CIIMAR, University of Porto, Rua dos Bragas, 289, Porto 4050-123, Portugal. vmvascon@fc.up.pt.
authors.forename: Vitor
authors.initials: V
authors.lastname: Vasconcelos
authors.affiliation: Department of Pharmacology, Veterinary Faculty, University of Santiago de Compostela, Lugo 27002, Spain. luis.botana@usc.es.
authors.forename: Luis
authors.initials: L
authors.lastname: Botana
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid; D005453:Fluorescence; D049851:Gastropoda / Q000737:chemistry*; D008623:Mercaptoethanol / Q000737:chemistry; D010084:Oxidation-Reduction; D012530:Saxitoxin / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry; D013215:Starfish / Q000737:chemistry*
chemical_list: D012530:Saxitoxin; D008623:Mercaptoethanol; C034902:neosaxitoxin; C013007:gonyautoxins
keywords: interfering matrix peaks; paralytic shellfish poisoning; post-column oxidation fluorescence; thiol compounds; toxins