ESTIMATION OF AN EXTRACTION TECNIQUE FOR ORGANOCHLORINATED CONTAMINANTS IN BIOTA AND MARINE SAMPLES

In this article we present evaluation of an analytical technique for the extraction of organochlorinated pesticides and polychlorinated biphenyls (PCB) in biota samples and marine sediments. For extraction of organochlorinated pollutants different methods are currently used: from classical Soxhlet extraction to automated extractions method as accelerated solvent extraction (ASE) and supercritical fluid extraction (SFE). For solid samples ultrasonic extraction is widespread for its facilities. To introduce this last method for biota and sediment marine samples, CRM of mussels homogenate IAEA-435 and sediment marine sample IAEA-383 were used. Reference method for marine pollution studies 71 was used as standard technique for extraction of biota and sediment samples using Soxhlet extraction for organochlorinated pollutants. Ultrasonic extraction was used for the same reference samples. Different solvent mixtures, time and temperature of the extraction were used for optimising extraction technique for both samples. Clean-up procedure was the same after each extraction for biota sample based on lipid hydrolysis using sulphuric acid treatment in a Florisil filled column. The extract of sediment sample was 'cleaned' also in the same way for both extraction techniques using metallic mercury for elementary sulphur removal. Quantification of organochlorinated compounds was performed by gas chromatography technique. Ultrasonic extraction technique was more efficient, more easily to be used, shorter in time and also required a smaller quantity of solvent.