Amperometric proton selective strip-sensors with a microelliptic liquid/gel interface for organophosphate neurotoxins

• Published in: Electrochemistry communications Vol. 13; no. 6; pp. 611 - 614
• Main Authors: Hossain, Md. Mokarrom, Faisal, Shaikh Nayeem, Kim, Chang Sup, Cha, Hyung Joon, Nam, Sang Cheol, Lee, Hye Jin
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.06.2011; Amsterdam Elsevier; New York, NY
• Subjects: Analytical chemistry; Chemistry; Electrochemical methods; ETH 1778; Exact sciences and technology; Liquid/gel interface; Organophosphorus hydrolase; Paraoxon; Strip-sensors; Organophosphorus hydrolase; Strip-sensors; ETH 1778; Paraoxon; Liquid/gel interface; Insecticide; Esterases; Phosphorus Organic compounds; Phosphoric triester hydrolases; Strip electrode; Liquid liquid interface; Amperometry; Proton; Ionophore; Polyvinyl chloride; Interface two immiscible electrolyte solution; Dimethylsiloxane polymer; Enzyme; Pesticides; Non miscible liquid; Electrochemical detector; Toxin; Neurotoxin; Organic phosphate; Hydrolases; Organophosphorus compounds; Interface
• ISSN: 1388-2481; 1873-1902
• DOI: 10.1016/j.elecom.2011.03.024

A novel strip-based disposable amperometric proton sensor that can selectively detect organophosphate neurotoxins ( i.e., paraoxon) is described. The detection methodology is based on measuring the current change involved in the assisted proton transfer by a proton selective ligand ( e.g., ETH 1778) across a microelliptic hole interface between the aqueous and polyvinylchloride-2-nitrophenyloctylether gel phase. The selective detection of paraoxon is achieved by measuring protons released by the specific hydrolysis of paraoxon with the organophosphorus hydrolase enzyme. A two-step process involving the hydrolysis and proton transfer reaction was characterized using cyclic voltammetry and differential pulse stripping voltammetry. A strip-based sensor fabricated using a simple polydimethylsiloxane (PDMS) mold with the resulting device was found to exhibit a linear response over a wide range of paraoxon concentrations (0.5 μM–100 μM) present in aqueous samples. In addition to the excellent detection limit and a wide dynamic range, a superb selectivity in the presence of common interfering agents in agricultural samples is achieved. ► Amperometric proton sensor for paraoxon with ion transfer reaction across an ITIES. ► Disposable strip-sensors are prepared via a simple PDMS microfabrication method. ► Paraoxon selective detection via hydrolysis followed by assisted proton transfer. ► Extended linear response over a wide dynamic range of paraoxon concentrations. ► Good detection limit with excellent selectivity over other electrochemical methods.