Optimization of Solid-phase Extraction and GC-MS/MS Determination of PAHs in Bulgarian Sewage Sludge

Abstract

In this study, a method for the solid-phase extraction (SPE) and GC-MS/MS determination of the priority polycyclic aromatic hydrocarbons (PAHs) in sewage sludge was developed. Two types of SPE sorbents (C18 ec and HLB) were evaluated for the separation and pre-concentration of the analytes. The initial extraction from the sludge matrix, column conditioning, and final elution were optimized using organic solvents of varying polarities, and the recovery for each PAH was evaluated. Satisfactory recoveries (96–114%) for all PAHs were achieved using acetone for the initial extraction, HLB (500 mg/3 mL) SPE columns, conditioning with dichloromethane – acetonitrile, and elution with acetone. The optimized method was applied to the analysis of PAHs in sewage sludge from Bulgarian wastewater treatment plants (WWTPs). Total PAH concentrations in urban sludge ranged from 393 μg/kg to 1780 μg/kg, while mixed domestic--industrial exhibited a higher concentration of 5980 μg/kg.