Simultaneous determination of nitroaromatic compounds in water using capillary electrophoresis with amperometric detection on an electrode modified with a mesoporous nano-structured carbon material

In this article, a carbon disk electrode modified with mesoporous carbon material (CMK-3) was used in CE with amperometric detection system for the simultaneous determination of four types of important nitroaromatic compounds, including 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitrobenzene (TNB), 2,4-dinitrotoluene (DNT) and 1,3-dinitrobenzene (DNB). Compared with the bare carbon electrode, the CMK-3 modified electrode greatly improved the sensitivity at a relatively positive detection potential due to its excellent electrocatalytic activities, high conductivity and large effective surface area. The four analytes could be well separated and detected within 480 s. A good linear response was obtained for TNB, DNB, TNT and DNT from 8.4 to 5.0 × 10³ μg/L, with correlation coefficients higher than 0.9992. And the detection limits were established between 3.0 and 4.7 μg/L for the four investigated nitroaromatic compounds (S/N = 3). The CMK-3-modified electrode was successfully employed to analyze coking wastewater, tap water and river samples with recoveries in the range of 94.8-109.0%, and RSDs less than 5.0%. The presented results demonstrated that the CMK-3-modified carbon electrode used in CE with amperometric detection was of convenient preparation, high sensitivity and good repeatability, which could be employed in the rapid determination of practical samples.