Analysis of palytoxin-like in Ostreopsis cultures by liquid chromatography with precolumn derivatization and fluorescence detection

A rapid liquid-chromatography (LC) method is presented which uses fluorescence detection (FLD) for palytoxin analogues analysis in benthic dinoflagellates of the genus Ostreopsis. The amino-acidic reagent 6-aminoquinolyl-N-hydroxisuccinimidyl carbamate (AccQ) was used for fluorescence labelling followed by LC–FLD.The efficacy of the method is exemplified by comparison of the results of the quantification obtained by LC–FLD and the hemolytic assay performed for palytoxins for which a highly significant linear correlation was achieved (r2 = 0.9118). The derivatized palytoxin analogues were determined in the range of 0.75–25 ng.The proposed method was successfully applied to the determination and quantification of palytoxin analogues in 14 samples from different strains of Ostreopsis from different locations (Western Mediterranean Sea, Canary Islands, Madeira Islands and Southern coasts of Brazil). To confirm the chemical structure of the toxins, samples were also analyzed by liquid chromatography coupled with mass spectrometry (LC–MS) with a system that has a poorer sensitivity when compared with LC–FLD detection and the hemolytic assay. The successful use of this method with dinoflagellates is a good indicator of suitability for other types of marine samples.