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.