Improved chemical hydrolysis conditions for the high conversion of the paralytic shellfish toxins GC4 and GC5 into their decarbamoyl analogues dcGTX1 and dcGTX4

Abstract

The chemical methodology to quantify paralytic shellfish toxins (PSTs) is ultrahigh-performance liquid chromatography with fluorescence detection and precolumn oxidation. It has been established as the European Union (EU) reference method replacing the mouse bioassay. There are some alternatives to this method for a better quantification of the whole range of PSTs; however, the detection of GC toxins in mollusks is still a challenge since they are retained when the C18 solid phase extraction (SPE) procedure is used to remove interferences. In addition to that they are not often included in the detection and quantification methods because of the lack of reference standards. Due to this in this work a new method is proposed to convert GC4 and GC5, for which analytical standards are not commercially available, into their decarbamoyl analogues dcGTX1 and dcGTX4, respectively. It was possible the conversion of these toxins, and the experimental conditions were tested and established regarding pH, temperature and time for the hydrolysis.