Simplification of the Procedure of Preparing Samples for PAHs and PCBs Determination / Uproszczenie Procedury Przygotowania Próbek Do Oznaczania Wwa I Pcb
Archives of Environmental Protection
The work presents examination results of the common determination of PAHs and PCBs in industrial sludge and supernatants. Sewage sludge was taken from the wastewater treatment plant, and supernatants were obtained by their centrifuging. The prepared samples of sewage sludge and supernatants were subjected to extraction with applying the mixture of organic solvents. Cyclohexane and dichloromethane were used for constant samples, and methanol, cyclohexane and dichloromethane -for liquid.
... or liquid. Extracts, after separation from samples of sewage sludge and supernatants, were cleared on the silica gel in vacuum conditions and concentrated in the stream of nitrogen. In such prepared extracts there was conducted the qualitative-quantitative analysis of 16 PAHs using the GC-MS system. Next, the samples were evaporated and poured with water and methanol until the clear solution was obtained. Extracts were cleared on octadecyl C18 columns, and then concentrated in the nitrogen stream. In these extracts PCBs was also determined with the application of the gas chromatograph with mass spectrometer. The range of concentrations 16 PAHs in sewage sludge equalled 10-16 mg/kg d.w. . Summary average concentration 16 PAHs in supernatants was reached 17 μg/L. Average recovery of PAHs introduced to sewage sludge in the form of reference mixture was 78% (with consideration of naphthalene). In the case of supernatants, the average value of recovery reached 60%. Average PCBs concentration in supernatants equalled 10 ng/L. For sewage sludge the sum of marked PCBs was an average 1.23 μg/kg d.w. . In the case of particular PCBs the percentage recovery of the reference mixture for supernatants was 86%, while for sewage sludge it was 55%.