DETERMINATION OF POLYNUCLEAR AROMATIC HYDROCARBONS (PAHs) IN SEWAGE SLUDGE BY MICELLAR ELECTROKINETIC CAPILLARY CHROMATOGRAPHY AND HPLC-FLUORESCENCE DETECTION: A COMPARATIVE STUDY

Two different methods, based on micellar electrokinetic capillary chromatography (MECC-DA) and high performance liquid chromatography (HPLC)-fluorescence detection, were studied to separate and determine 12 polynuclear aromatic hydrocarbons (PAHs) of 16 PAHs recommended by the Environmental Protection Agency (EPA) in sewage sludge. beta-cyclodextrin was used as a micelle precursor in a sodium borate buffer solution which included the surfactant sodium dodecyl sulphate (SDS) and the acetonitrile dissolvent. The following parameters: temperature, voltage, pH, concentrations of buffer solution and injection time, were optimized by an experimental design (Nemrodw programme). Furthermore, HPLC-fluorescence detection and separation conditions are reported. The mobile phase was acetonitrile-water in different percentages. Precision, accuracy, linearity and detection and quantification limits were determined. This method was applied in the analysis of sewage sludge from a wastewater depuration station in Crispijana (Alava, Spain). In this case, it is necessary to carry out a solid phase extraction step for its determination. The method was validated by the analysis of a certificated sample of LGC 6182, and finally samples of sewage sludge were analysed weekly for two years, obtaining in all cases results under the legal limits for the use of sewage sludge in agriculture.