Multiresidue determination of pesticide in fishery products by a tandem solid-phase extraction technique

In order to simplify the survey of pesticide (including carbamate, organochlorine, organophosphate and synthetic pyrethroid pesticides) residues in fishery products (including bivalve, crustacean, fish and cuttlefish), multiresidue determination methods were developed through a solid phase extraction (SPE) technique. In the present procedures, samples were extracted with acetonitrile except for bivalve and cuttlefish samples. Mixed solvent of water, acetone and acetonitrile was added to bivalve prior to homogenization, whereas water was needed in cuttlefish samples for blending. For both kinds of sample, an additional procedure of salting-out was needed during extraction. Tandem SPE cartridges of C18 and aminopropyl, using acetonitrile as the only solvent, were used to clean up extracts from either method. A total of 91 pesticides in four major pesticide groups were tested in this study. Gas chromatography (GC, equipped with electron capture detector and flame photometric detector) and high-performance liquid-chromatography (HPLC) equipped with fluorescence detector were used for analysis. The validation of the method was evaluated for each fishery product using samples spiked with all pesticide standards at three concentration levels. The results indicated percentage of recovery ranged from 60% - 120% and coefficients of variation < 20% for all but 10 of the pesticides analyzed (including 1-naphthol, 3-hydroxy carbofuran, aldicarb sulfoxide, heptachlor, trifuralin, acephate, dichlorvs, methamidophos, monocrotophos and omethoate). Residue extraction techniques described in this report are rapid and suitable for screening of pesticide residues in monitoring programs.