A Highly Sensitive Impedimetric Metamitron Microsensor Based on All-Solid-State Membrane Using a New Ion-Pair Complex, [3,3′-Co(1,2-closo-C₂B₉H₁₁)₂]⁻[C₁₀H₁₁ON₄]⁺

Abstract

An all-solid-state impedimetric microsensor based on impedimetric measurements for detecting the herbicide metamitron (MM) is reported in the present work. For this purpose, a novel metamitron ionophore has been prepared. It was based on the isolation of the metamitron monoprotonated form coupled to the metallocarborane anion, cobalt bis (dicarbollide), ([3,3′-Co(1,2-closo-C2B9H11)2]−) as an ion-pair complex of the type [3,3′-Co(1,2-closo-C2B9H11)2]−[C10H11ON4]+. Once the ion-pair complex was synthetized, it was incorporated to a PVC-type membrane including o-Nitrophenyloctylether (o-NPOE) as plasticizer. The membrane was then drop-cast on top of polypyrrole-modified gold working microelectrodes. A quick response of 30 s has been provided by the microsensor in the range of metamitron concentrations between 10−8 M and 10−4 M with a limit of detection of 10−8 M. Furthermore, it was highly selective toward metamitron, when compared to some possible interfering compounds as imazapic and carbetamide.

Keywords

• metamitron
• ion-pair complex
• microsensor
• metallocarboranes
• herbicides
• triazines