Method development and application for the determination of polycyclic aromatic hydrocarbons (PAHs) in KwaZulu-Natal, South Africa.

Abstract

This work involved the analysis of PAHs under optimized conditions of gas chromatographymass spectrometry (GC-MS) method and after extracting by optimised ultrasonic extraction (USE) (for sediment samples) and solid phase extraction (SPE) (for water samples). The accuracy of the entire optimized methods was checked by analysing spiked water and sediment samples at single level representing the natural anticipated concentration levels in the respective matrices. Analytical performance of parameters such as linear range, limit of detection (LOD), limit of quantification (LOQ), extraction efficiency were determined as part of quality assurance. The optimized methods were then applied for the analysis of PAHs in real water and sediment samples. The LOD and LOQ for the optimized SPE method ranged from 0.01- 0.17 µg/L and 0.05-0.5 µg/L. The LOD and LOQ for the optimized USE ranged from 0.008-0.09 and 0.03-0.20 µg/kg. The percentage recoveries obtained under optimum conditions ranged between 87-121% for SPE and 83-117% for ultrasonic with the relative standard deviation (RSD) of less than 10% for both methods. The concentration levels of PAHs obtained in wastewater, river water and dam water were between 0.186-7.74 µg/L, 2.17-32.94 µg/L and 2.5-3.3 µg/L, respectively. The concentration levels of PAHs obtained in river and dam sediment samples were between 2.8-42.0 µg/kg and 2.8-3.9 µg/kg, respectively.