Graphene Functionalized with Imidazole Derivatives as Nanotransducers for Electrochemically Detecting Isothiazolinone Biocides

Abstract

Isothiazolinones, which are widely used as chemical additives in many industries, may lead to skin irritation and allergies, thereby adversely influencing human health and the environment. Therefore, this paper proposes an efficient strategy for screening nanohybrid transducers to selectively detect 2-octyl-3-isothiazolinone (OIT) as a representative isothiazolinone. Chemical receptor (CR) candidates consisting of two parts: a reactive imidazole unit and side functional group for covalent conjugation with graphene and noncovalent interaction with the target, respectively, were designed. Five CR structures were selected and synthesized based on density-functional-theory calculations. The synthesized CRs were anchored to graphene for electrochemical transduction. The alkyl groups calculated to have the highest chemical affinities toward OIT were introduced in the CR/graphene nanohybrids (CGNHs). The electrochemical responses of the CGNHs toward OIT depended on the CR type, OIT concentration, and applied potential. Therefore, the combination of five CGNHs as a transducer with different potentials enabled the facile and effective detection of OIT (1–200 mg L–1) from the interferences through principal component analyses. The best CR corresponded to the dodecyloxy group, and the optimal measurement conditions included a scan rate of 25 mV s–1 and applied potentials of −0.75, 0.08, and 1.30 V (vs Ag/AgNO3). The proposed strategy can facilitate the efficient development of nanotransducers for identifying different types of chemical species such as biocides.