Cholinesterase sensors based on screen-printed electrodes for detection of organophosphorus and carbamic pesticides

Abstract

Cholinesterase sensors based on screen-printed electrodes modified with polyaniline, 7,7',8,8'-tetracyanoquinodimethane (TCNQ), and Prussian blue have been developed and tested for detection of anticholinesterase pesticides in aqueous solution and in spiked grape juice. The influence of enzyme source and detection mode on biosensor performance was explored. It was shown that modification of the electrodes results in significant improvement of their analytical characteristics for pesticide determination. Thus, the slopes of the calibration curves obtained with modified electrodes were increased twofold and the detection limits of the pesticides were reduced by factors of 1.6 to 1.8 in comparison with the use of unmodified transducers. The biosensors developed make it possible to detect down to 2 x 10(-8) mol L(-1) chloropyrifos-methyl, 5 x 10(-8) mol L(-1) coumaphos, and 8 x 10(-9) mol L(-1) carbofuran in aqueous solution and grape juice. The optimal conditions for grape juice pretreatment were determined to diminish interference from the sample matrix.

Cholinesterase-based biosensors

“…The enzymatic activity can be detected by means of the oxygen decrease measurement using Clark's electrode 64 or the increase of hydrogen peroxide 65 which can be measured amperometrically at around +600 mV versus Ag/AgCl using a platinum electrode. Moreover it is possible to achieve the decreasing of the applied potential by using of redox mediators, such as prussian blue 66,67 , ferophthalocyanine 68 , or by adopting novel materials such as carbon nanotubes 69,70 . Multi-walled carbon nanotubes-modified screen-printed carbon electrodes offer a significant catalytic effect for the reduction and oxidation of hydrogen peroxide 70 .…”

Modified Cholinesterase Technology in the Construction of Biosensors for Organophosphorus Nerve Agents and Pesticides Detection

“…In case of cholinesterase biosensors it is possible to lower the voltage and interferences of electroactive sample components by means of redox transmitters such as ferophtalocyanine, cobalt phtalocyanine, Prussian blue (ferrihexacyanofferate), 7,7,8, in combination with carbon electrodes, screen electrodes or using the carbon nanotube (CNT) (Arduini et al, 2007;Ciucu et. al., 2003;Hart et al, 1997;Hernandez et al, 2000;Lin et al, 2004;Ricci et al, 2003;Ivanov et al, 2003a;Nunes et al, 2004;Shulga & Kirchhoff, 2007;Skládal, 1992;Skládal & Mascini, 1992;Suprun et al, 2005;Wring et al, 1989) or electrochemical decomposition of the arising peroxide using a gold or platinum amperometric electrode (Yao, 1983). CNTs are commonly used for electrochemical biosensors.…”

Carbon Nanotube-Based Cholinesterase Biosensors for the Detection of Pesticides

“…ChE immobilization was able to carry out by cross-linking method with glutaraldehyde vapour (Arkhypova et al, 2003(Arkhypova et al, , 2004(Arkhypova et al, and 2008. It was reported a ChE membrane formed on the electrode with ChE, Nafion and glutaraldehyde (Suprun et al, 2005;Ivanov et al, 2003). In this case, it was found that the use of albumin bovine serum at 3% increases the enzyme stability (Arduini et al, 2006;Laschi et al 2007).…”