Study on the Determination of Chlorobenzenes by Gas Chromatography with Electron Capture Detection (GC-ECD)

Chlorobenzenes (CBzs) are typical organic pollutants, however studies on detailed profiles of these substances in Vietnam are still limited. In this study, an analytical method for the simultaneous determination of 11 CBzs with 2 to 6 chlorine atoms was studied on a gas chromatography with electron capture detection (GC-ECD) system. CBzs were separated on a Rxi-5ms capillary column (30m × 0.25 mm × 0.25 µm). Nitrogen with a flow rate of 1 mL/min was used as carrier gas. Column oven temperature program was set as follows: 40 °C to 160 °C (10 °C/min, hold 1 min), to 220 °C (10 °C/min, hold 5 min), and to 300 °C (20 °C/min). Injector and detector temperatures were 220 °C and 300 °C, respectively. Exept for 1,2,3,5- and 1,2,4,5-tetracholorobenzenes with similar retention time, peaks of the remaining analyte pairs were well-resolved (RS > 1.5). Limits of detection of CBzs ranged from 1 ng/mL (hexachlorobenzene) to 50 ng/mL (dichlorobenzene isomers). Analytical signals exhibited linear correlation with CBzs concentrations up to 1000 ng/mL (R2 > 0.99). Some recovery tests for CBzs were conducted including: treatment with concentrated sulfuric acid, liquid liquid partitioning, solid phase extraction, and ultrasonic extraction.