Determination of organophosphorous flame retardants in fish tissues by matrix solid-phase dispersion and gas chromatography

Organophosphate esters (OPEs), utilized as flame retarding agents and/or plasticizers, are almost ubiquitous in environmental compartments, and biota and foods could be contaminated by bioaccumulation or during the treatment processes. A multiresidue method is proposed for the determination of 13 OPEs in fish tissues: analytes were simultaneously extracted and purified using the matrix solid phase dispersion technique and then determined by gas chromatography with nitrogen-phosphorus detection. The main parameters affecting extraction yield and selectivity, such as the type of dispersant material, clean-up co-sorbent, rinse and elution solvents, were evaluated to obtain lipid-free extracts and quantitative recoveries for OPEs. Under optimal conditions, 0.5 g of samples was dispersed with 2 g Florisil and 1 g anhydrous sodium sulphate and transferred to a solid phase extraction cartridge containing 1 g alumina. The lipids were removed using 5 mL n-hexane/dichloromethane (1:1) and analytes were recovered with 10 mL n-hexane/acetone (6:4) and directly analysed. The method developed provided recoveries between 70 and 110% for different kinds of fish, and the day-to-day variability was between 1 and 9%. This procedure constitutes the first analytical method for the analysis of OPEs in a food matrix and it is applicable to analyse a large number of samples to evaluate the occurrence and sources of OPEs in biota and foods.