Development, Validation, and Application of a Method Based on Reverse-Phase HPLC for the Simultaneous Determination of Six Organochlorine Pesticides in Surface and Groundwater Samples Collected from Northeast Libya

Abstract

The contamination by organochlorine pesticides (OCPs) of the selected sites in the eastern region of Libya was investigated to estimate the current status of pollution in surface and groundwater sources. This study was conducted to determine the concentrations of some OCPs residue in surface and groundwater samples collected from thirty different sites around Al-Jabal Al-Akhdar northeast of Libya during the summer, autumn, and winter seasons of 2016. A simple and rapid method based on the liquid-liquid extraction method followed by an HPLC with reversed-phase was developed to determine six OCPs in water samples simultaneously. An HPLC instrument was supplied with a C18 column (250 mm × 4 mm; 4.6 μm particle size) and a UV detector at 238 nm. The mobile phase was composed of 0.1% propanol in water and acetonitrile (25/75, v/v). The method was validated using reference standards of these six OPCs at different concentration levels and shows good linearity in the concentrations between 5.0 and 25 µg mL− 1. The LOD and LOQ ranged from 0.71 to 2.24 μg mL -1 and 2.16 to 6.79 μg mL-1, respectively. Relative standard deviation (%RSD) ranged from 0.026 to 0.673 %. The only OCP residue found in the area of study was 2, 4-D, with a variation of its residue levels during the seasons. The overall results showed that surface water was more polluted with 2, 4-D than groundwater, which was detected in the wide range of concentration of 0.037 to 0.385 μg mL-1, 0.003 to 0.047 μg mL -1 and 0.012 to 0.039 μg mL-1 during summer, autumn, and winter, respectively.