Determination of Chlorobenzenes in Wastewater by Single-Drop Microextraction Coupled to Capillary Gas Chromatography

This study describes an analytical method employing capillary gas chromatography (GC) using flame ionization detection (FID) that has been developed for the simultaneous determination of chlorobenzenes (m-dichlorobenzene (m-DCB), p-dichlorobenzene (p-DCB), o-dichlorobenzene (o-DCB) and 1,2,4-trichlorobenzene (1,2,4-TCB)) in wastewater. For this purpose, single-drop microextraction (SDME) was applied as a sample preparation technique. The SDME parameters such as types of extractants, volume of the microdroplet size, extraction time, stir rate and immersion depth of needle point were studyed and optimized. The method was linear in the ranges from 4.0×10-3 to 40.0 μg·mL-1 for m-DCB, p-DCB and o-DCB, and 4.0×10-3 to 30.0 μg·mL-1 for 1,2,4-TCB with R2≥ 0.9955. The SDME procedure allowed efficient recovery of the investigated chlorobenzenes ranging between 80 % and 105 % with a relative standard deviation (RSD) ≤6.5 for actual wastewater sampes spiked with 2, 5 and 10 μg·mL-1 of chlorobenzes, respectively. These results showed the potential of this technique for chlorobenzenes monitoring in wastewater samples. Furthermore, the investigated methods are simple, reliable, reproducible, and not expensive.