Liquid chromatography series dual‐electrode amperometric detection for aromatic nitro compounds

Abstract

A new design of dual-electrode electrochemical detector for liquid chromatography is described utilizing two series generator/detector electrodes. The detector developed is based on the larger electrode area design compared with commercial ones and has higher electrolytic efficiency, which lead to a higher detection sensitivity when in a reductive-oxidative series detection mode. Analytes are first reduced at the upstream electrode and the reaction products are then detected by oxidation at the downstream electrode. So, the influence of dissolved oxygen and trace amounts of heavy metals in the mobile phase and sample is eliminated. Thus, exhaustive removal of dissolved oxygen before analysis is not required. and the method can be easily automated. The technique is tested on seven aromatic nitro compounds. Under the optimized conditions, the assay is linear in a concentration range of 2.0 X lo--to 4.0 X 10-' g/mL and has low detection limits of 1.0 to 2.0 ng using a 10 FL sample. The largest standard deviation was 5.2%. The recovery of the detection of water samples was 93 to 107%.

Novel Signal-Amplified Fenitrothion Electrochemical Assay, Based on Glassy Carbon Electrode Modified with Dispersed Graphene Oxide

“…1 ). These reactions are consistent with other results reported for OPs and nitroaromatic compounds 20 21 22 23 24 25 26 . A two-step method was therefore used: the irreversible reduction peak was scanned from −0.2 to −1.0 V, and then the oxidation peak, which appeared at 0.024 V, was recorded, for detection and quantification of fenitrothion.…”

Electrochemical Sensor for Organophosphate Pesticides and Nerve Agents Using Zirconia Nanoparticles as Selective Sorbents

“…These profiles are consistent with those described elsewhere for nitroaromatic OP pesticides and nitrophenyl derivates. 25,[35][36][37] A control experiment (Figure 4b) was performed under the same conditions with the ZrO 2 /Au electrode in the absence of methyl parathion; no redox peak appeared at the selected potential range (the standard reduction potential of ZrO 2 is -1.544 V). SWV analysis has a higher sensitivity than other electrochemical technologies, such as cyclic voltammetry and differential pulse voltammetry.…”

Analytical Aspects of Amino, Quaternary Ammonium, Nitro, Nitroso and Related Functional Groups

“…This eliminates the influence of dissolved oxygen and trace amounts of heavy metals in the mobile phase and sample, and exhaustive removal of dissolved oxygen before injection is not required. The method can be easily automated 449 .…”