Optimization and Validation of LLE/HPLC-DAD Method to Determine the Residues of Selected PAHs in Surface Water

A rapid precise and accurate method was optimized and validated for the simultaneous determination of 6 PAHs (naphthalene, acenaphthalene, phenanthrene, fluoranthrene, anthracene and pyrene) in water by HPLC and their distribution in surface water (water from Yamuna river in Wazirabad and Okhla region and Aakulam lake, Kerala) were undertaken. The High-Pressure Liquid Chromatography (HPLC) separation of 6 PAHs was carried out by C-18 column with gradient elution of acetonitrile and water with diode-array detection (DAD). The method was optimized by using liquid–liquid extraction (LLE) with different solvent like hexane, dichloromethane and ethyl acetate and extract cleaned by adsorption column cleanup using different adsorbent like silica gel, alumina and florisil. Among the three solvents used for LLE, dichloromethane gave maximum extraction efficiency (70.2791.09%). For the cleanup of water extract, a florisil column using 20:80 acetone:hexane as the eluting solvent gave recovery of 91.2–97.2 μg and 8.9–9.6 μg at 100 μg and 10 μg of PAHs loaded in the column, respectively. The total method recovery using dichloromethane as the extracting solvent and 20:80 acetone: hexane as the eluting solvent for florisil column clean up varied from 71.02–89.74%. Limit of detection (LOD), limit of quantiucation (LOQ), and correlation coefficients were found in the range of 0.1 to 1.5 ig L−1, 0.5 to 4 ig L−1 and 0.994 to 0.999, respectively. No residues of PAHs were detected in any of the water samples other than the Okhla water samples. The PAHs detected in Okhla water sample were phenanthrene (3.51 μg L−1) and fluoranthrene (4.61 μg L−1).