Biosensor for direct determination of organophosphate nerve agents. 1. Potentiometric enzyme electrode

Towards a Capacitive Enzyme Sensor for Direct Determination of Organophosphorus Pesticides: Fundamental Studies and Aspects of Development

“…As can be seen from the figure, the highest hydrolytic rates have been obtained at pH 9. This value gives a difference of about 0.5 units between the optimum of the free and immobilised enzyme, but is in good correlation with experiments, which have been performed with OPH-based ISEs [3]. 5 shows the effect of conductivity (varying NaCl concentration) of the buffer on the potential of the biosensor.…”

“…After preparation of the pH-sensitive EIS transducer structures, OPH (produced and purified according to the protocol described in [3], specific activity of 587 U/mg protein) was immobilised on the pH-transducing materials by adsorption, cross-linking via glutaraldehyde and entrapment in nafion. For all experimental details, see [11].…”

“…Since the organophosphates are substrates of the enzyme this allows a direct detection method [3][4][5]. The present paper describes an OPH-based capacitive EIS biosensor for the direct determination of pesticides.…”

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

“…So the organophosphorus compounds act for OPH as a substrate. These types of biosensors offer, same as the cholinesterase ones, using optical, fluorescent, potentiometric or amperometric converters (Karnati et al, 2007;Mulchandani, et al 1999aMulchandani, et al , 1999bRogers et al, 1999;Wang et al, 2003). Also a field version for in-situ monitoring has been developed Mulchandani et al, 2001).…”

An Organophosphate Sensor Based on Photo-crosslinked Hydrogel-entrapped E. coli

“…3 Because of its specificity, the OPH enzyme has been used for sensing [5][6][7] and detoxifying OPs. 8,9 However, a major problem of this naked OPH enzyme is that it shows a significant decrease in enzyme activity and stability after immobilization of the enzyme within or on a matrix.…”