Ultrasonic-assisted water extraction and solvent bar microextraction followed by gas chromatography–ion trap mass spectrometry for determination of chlorobenzenes in soil samples

A novel and simple analytical method for the determination of chlorobenzenes (CBs) in soil samples was developed using ultrasonic-assisted water extraction (UAWE) coupled with solvent bar microextraction (SBME). Four chlorobenzenes, 1,2,3-trichlorobenzene (1,2,3-TCB), 1,2,3,4-tetrachlorobenzene (1,2,3,4-TeCB), hexachlorobenzene (HCB), and 1-chloro-4-nitrobenzene (1-C-4-NB), were used as model compounds to investigate the extraction performance. Parameters affecting the extraction efficiency were investigated in detail. UAWE was used for the extraction of CBs from 1.0 g of sediment using 10 mL of ultrapure water at 100 W for 30 min at 30–35 °C. The extract was subsequently subjected to a single step SBME cleanup and enrichment procedure. Both ends of the solvent bar with about 4 μL of 1-octanol were sealed by a sealing machine, and it was placed in the soil slurry for extraction. After extraction, analysis was carried out by gas chromatography–ion trap mass spectrometry (GC–ITMS) detection. The relative recoveries from the spiked soil sample varied between 93 and 105% for CBs, and exceeded levels achieved for conventional Soxhlet extraction. The method linearities were 10–150, 40–600, and 100–1500 ng g−1 for different CBs. The limits of detection (LODs) and the limits of quantification (LOQs) were in the range of 0.7–27.3 ng g−1 and 2.2–90.9 ng g−1, respectively. Good reproducibilities were obtained with relative standard deviation (RSD) values below 6.8%. The analytical potential of the method was demonstrated by applying the method to spiked soil sample.