Towards a Capacitive Enzyme Sensor for Direct Determination of Organophosphorus Pesticides: Fundamental Studies and Aspects of Development
نویسندگان
چکیده
The realisation of a miniaturised potentiometric enzyme biosensor is presented. The biosensor chip utilises the enzyme organophosphorus hydrolase (OPH) for the direct determination of pesticides. The transducer structure of the sensor chip consists of a pHsensitive capacitive electrolyte-insulator-semiconductor (EIS) structure that reacts towards pH changes caused by the OPH-catalysed hydrolysis of the organophosphate compounds. The biosensor is operated versus a conventional Ag/AgCl reference electrode. Measurements were performed in the capacitance/voltage (C/V) and constant capacitance (ConCap) mode for the two different pesticides paraoxon and parathion. For the development of this new type of biosensor, different immobilisation strategies, influence of buffer composition and concentration, transducer material, detection limit, long-term stability and selectivity have been studied.
منابع مشابه
A capacitive field-effect sensor for the direct determination of organophosphorus pesticides
A novel capacitive field-effect sensor for the direct determination of organophosphorus pesticides by the enzyme organophosphorus hydrolase (OPH) is presented. The enzyme OPH hydrolyses organophosphorus compounds catalytically, thus releasing Hþ ions. By means of a silicon-based field-effect sensor, which consists of a layer sequence of Al/p-Si/SiO2 with alternative pH-sensitive materials (Ta2O...
متن کاملDetermination of Twenty Organophosphorus Pesticides in Wheat Samples from Different Regions of Iran
Background: Organophosphorus pesticides are widely used in agriculture, homes, gardens, and veterinary practices. Extensive application of pesticides in agriculture often results in residues of these compounds being absorbed into the foods, including wheat. The aim of this study was to evaluate the residue levels of 20 organophosphorus pesticides in wheat samples collected from different region...
متن کاملMultiresidue determination of organophosphorus pesticides in corn oil using solid-phase extraction with lanthanum silicate sorbent and gas chromatography
Phosalone, malathion and diazinon were analyzed in corn oil using solid phase extraction (SPE)with lanthanum silicate as a new solid sorbent followed by gas chromatography with nitrogenphosphorus detection (GC-NPD). The efficiency of different eluents (methanol, dichloromethane,ethyl acetate, dichloromethane — ethyl acetate (1:1) and ethyl acetate — methanol (1:1)) werecompared for elution of o...
متن کاملDesign of High Sensitivity and Linearity Microelectromechanical Systems Capacitive Tire Pressure Sensor using Stepped Membrane
This paper is focused on a novel design of stepped diaphragm for MEMS capacitive pressure sensor used in tire pressure monitoring system. The structure of sensor diaphragm plays a key role for determining the sensitivity of the sensor and the non-linearity of the output.First the structures of two capacitive pressure sensors with clamped square flatdiaphragms, with different thicknesses are inv...
متن کاملDevelopment of a microtiter plate ELISA and a dipstick ELISA for the determination of the organophosphorus insecticide fenthion.
In previous studies, polyclonal antibodies against the organophosphorus insecticide fenthion were obtained and an indirect competitive enzyme-linked immunosorbent assay (ELISA) was developed for this pesticide. In this study, using these antibodies and an enzyme tracer, direct competitive ELISAs for fenthion in microtiter plate and dipstick formats were developed. The microtiter plate ELISA sho...
متن کامل