Determination of Chlorobenzenes and Nitrobenzoates in Wastewater by Dispersive Liquid-Liquid Microextraction Coupled to Capillary Gas Chromatography

Abstract

A fast, eco-friendly and reliable method combining dispersive liquid-liquid microextracion (DLLME) with capillary gas chromatography (GC) was developed for the simultaneous determination of p-dichlorobenzene (p-DCB), o-dichlorobenzene (o-DCB), nitrobenze (NB), 1,2,4-trichlorobenzene (TCB), and 3-nitrotoluene (NT) in wastewater. To achieve this goal, dispersive liquid-liquid microextraction (DLLME) was applied as a sample preparation technique. The DLLME parameters such as the types and volume of extraction solvent, the types and volume of the disperser solvent, pH value and salt addition were investigated and optimized. The method was linear in the ranges from 2.2 × 10 -2 to 200 µg·mL -1 for aforementioned compounds with R 2 ≥ 0.9987. The DLLME procedure allowed efficient recovery of these compounds ranging between 89 % and 104 % with a relative standard deviation (RSD) ≤ 9.6 (n=6) for genuine wastewater samples spiked with 10, 50 and 100 µg·mL -1 of standard substances, respectively. These results showed the potential of this technique for chlorobenzenes and nitrobenzoates monitoring in wastewater samples. Furthermore, the methods are simple, reproducible, and inexpensive.