Analysis of pesticide residues in seaweeds using matrix solid-phase dispersion and gas chromatography-mass spectrometry detection

Products containing organophosphates, carbamates and pyrethroids pesticides, employed as chemother-apeutants in aquaculture, can remain as residues in the marine environment. Matrix solid-phase dispersion (MSPD) was developed to extract seventeen pesticides from seaweed samples using Florisil and graphitized carbon black as clean-up adsorbents prior to gas chromatography-mass spectrometry (GCMS) determination. The extraction has been optimised by a Box-Behnken design. The optimal conditions were 1 g of seaweed sample, 4 g of anhydrous sodium sulphate as dispersant, 3.6 g of Florisil and 0.4 g of GCB and an elution volume of 14 mL of a hexane:ethyl acetate mixture containing 40% ethyl acetate. The recoveries ranged from 81.6% to 113.2% with relative standard deviations (RSDs) ranging from 1.6% to 13.2%. The limits of detection (LOD) ranged from 0.5 to 2.9 ngg(-1). Internal quality control was successfully carried out to verify the quality of the data obtained in the analysis of these pesticides in seaweed samples. (C) 2012 Elsevier Ltd. All rights reserved.