A new method based on headspace adsorptive accumulation using a carboxylated multi-walled carbon nanotubes modified electrode: application for trace determination of nitrobenzene and nitrotoluene in water and wastewater

Abstract

A carboxylated multi-walled carbon nanotubes modified glassy carbon (MWCNTs-GC) electrode was fabricated via the drop-casting of a carboxylated carbon nanotubes suspension onto a glassy carbon electrode. A headspace adsorptive accumulation on the surface of the multi-walled carbon nanotubes modified glassy carbon electrode coupled with cyclic voltammetry has been established for analyzing nitrobenzene and 4-nitrotoluene in water samples. Factors which affect the extraction efficiency (modifier amount, pH, extraction temperature, extraction time, salt addition) have been investigated. The calibration plot for the determination of nitrobenzene and 4-nitrotoluene are linear in the wide ranges of 10–4000 ng mL⁻¹ and 20–6000 ng mL⁻¹ respectively. Under optimal extraction conditions, the detection limits (at S/N = 3) for nitrobenzene and 4-nitrotoluene were 3.0 ng mL⁻¹ and 6.0 ng mL⁻¹ respectively. The proposed method has been applied successfully for the determination of nitrobenzene and nitrotoluene in water and wastewater samples within a recovery range of ca. 97.5–103.33%.