Salt clean-up procedure for the determination of domoic acid by HPLC

Domoic acid (DA) was first reported in mussels from Prince Edward Island, Canada, in 1987. It reappeared in anchovies and pelicans from Monterey Bay, California, in 1991. Later that year, domoic acid was found in razor clams and Dungeness crabs along the Washington and Oregon coasts. Since the initial outbreak, a variety of analytical methods for the detection of this neurotoxin have been developed. Here, we describe a modification to the solid phase extraction (SPE) clean-up step in Quilliam's HPLC-UV method (1991: NRCC No. 33001). The standard 10% acetonitrile (MeCN) wash and 0.5M ammonium citrate buffer (ACB) in 10% MeCN (pH = 4.5) eluting solution have been replaced with a 0.1M sodium chloride (NaCl) in 10% MeCN wash and a 0.5M NaCl in 10% MeCN eluting solution. This modification allows the analysis to work equally well on both clam and crab viscera and meat. Chromatograms of visceral samples no longer contain interfering or late eluting peaks; and all chromatograms are free of the large solvent peak tailing associated with the ACB eluent. The newly modified method allows for an improved and more versatile domoic acid analysis.