An integrated method for the simultaneous determination of alkylphenol ethoxylates and brominated flame retardants in sewage sludge samples by ultrasonic-assisted extraction, solid phase clean-up, and GC-MS analysis

• Ultrasonic extraction coupled with SPE clean-up was used for isolation of the targeted analytes from solid samples.
• Acceptable recoveries of the target compounds based on precision (RSD < 15) and shorter analysis time were achieved (two classes of compounds analysed simultaneously).
• The proposed method showed adequate limit of quantification for environmental monitoring.
• Developed method was found to be reliable and sensitive to APEs and BFRs in environmental sludge samples.

Generally, a major route of alkylphenol ethoxylates (APEs) and brominated flame retardants (BFRs) to enter the environment is via the wastewater treatment works (WWTW) facilities. Consequently, the levels of APEs and BFRs in sewage sludges may give an indication of the general use and exposure of these compounds. The present study was aimed at an integrated method for the analysis and quantification of APEs and BFRs in sewage sludge from selected wastewater treatment plants. The optimization of the extraction procedure included variation of the amount of extracted biomass, the duration, temperature during sonication as well as type of extraction solvent. Chromatographic determinations of APEs and BFRs were carried out with gas chromatography equipped with mass spectrometry detector after derivatization with heptafluorobutyric anhydride (HFBA). The mean percentage recoveries ranged from 39% to 79% (n = 3) for sewage sludge after extracting 5 g biomass sludge with hexane: acetone (4:1) at 55 °C for 45 min in two cycles. The mean concentrations of APEs obtained ranged from < LOQ to 365 ng g− 1, < LOQ to 166 ng g− 1, < LOQ to 642 ng g− 1 while the concentration of BFRs obtained range from < LOQ- 17 ng g− 1, < LOQ to 163 ng g− 1, < LOQ to 14 ng g− 1 for sludge samples from Leeuwkuil, Rietspruit, and Sebokeng, respectively. All compounds, except for nonylphenol (NP), BDE47, and BDE154, were detected from the Rietspruit WWTW. The presence of these pollutants in Rietspruit WWTW may be attributed by the fact that this treatment plants treat wastewater from domestic as well industrial discharges from the surrounding area.