Determination of dinophysis toxin-3 by the LC-LC method with fluorometric detection

A highly sensitive HPLC method for the determination of acid dinophysis toxins-3 (DTX-3s; 7-O-acyl-35-methylokadaic acids) by labeling 2-(anthracene-2,3-dicarboximido)ethyl trifluoromethanesulfonate (AE-OTf) has been reported. The digestive glands of mussels or scallops were homogenized with 2-propanol, followed by extraction with hexane/ethyl acetate. After evaporation of the solvent, they were labeled with AE-OTf in dry acetonitrile. Then, after cleaning up with a silica-gel short column, the fluorescent derivatives were injected into an HPLC system. Tn this system, the derivatives were at first separated on a phenylated silicagel column; then, only the target fraction was introduced into a separation column (an ODS column) by a valve device for switching the column. The 7-O-palmitoyl DTX-3 derivative could be determined in the range of 1.4 - 284 fmol (1.5 - 300 pg) on the column. The detection limit was 0.57 fmol (0.6 pg, S/N=3).