COMPARATIVE-STUDY OF THE STABILITY OF SAXITOXIN AND NEOSAXITOXIN IN ACIDIC SOLUTIONS AND LYOPHILIZED SAMPLES

Paralytic shellfish poison (PSP) has historically been a problem for t he shellfish industry. In order to prevent the marketing of contaminat ed seafood products, governments have implemented monitoring programs where standards of toxins are necessary. The stability of these standa rd toxins is very important. In this paper we analysed the stability o f saxitoxin (STX) and neosaxitoxin in acidic solution and lyophilized samples. Individual toxins were determined in each sample using a high -performance liquid chromatographic procedure employing postcolumn oxi dation of the toxins to form fluorescent derivatives. Our results demo nstrate that STX is very stable in solution samples and could be adopt ed as a reference standard. This toxin can be kept in dilute acidic so lutions for 18 months without loss of potency. However, neosaxitoxin i s unstable, possibly due to transformation