Organophosphate biosensors sensors

More recently, other types of enzymatic biosensors have developed based on thermistor or opto-electronic sensors. Pogacnik and Franko (2003) presented a photother-mal biosensor for the determination of low concentrations of organophosphate and carbamates pesticides in vegetables without sample treatment. 

A set of qualitative results gained by a prediagnostic (qualitative) biosensor kit (OP-Prot sensor) developed for organophosphate and/or carbamate pesticide detection also arrived for RM08 and RM10. In case of the presence of pesticide mixtures, e.g. as it is the case in most natural samples, the kit detects unselectively the traces of all the present organophosphate and carbamate pesticides. The LOD of the applied kit is 0.1 — 10 pig L-1 depending on the pesticide. 

Piezoelectric sensors have become a versatile tool in biosensorics to study protein-protein and protein-small molecule interactions. Here we present theoretical background on piezoelectric sensors and instructions, how to modify their surface with various recognition elements for cholinesterases. These recognition elements comprise an organophosphate (paraoxon), a cocaine derivative (BZE-DADOO), and a tricyclic, aromatic compound (propidium). Additionally, a guide to the kinetic evaluation of the obtained binding curves is given in this chapter. 

Hartley, l.C. and J.P. Hart (1994). Amperometric measurement of organophosphate pesticides using screen-printed disposable sensor and biosensor based on cobalt phthalocyanine. Ana/. Pmc. 31(11), 333—337. 

Environmental sensors. Eleetrochemical biosensors make it possible to do real time, on-site environmental monitoring. This is important for water supplies, ponds, rivers, soil runoff, and wastewater treatment faeilities. Pestieides are the most commonly studied analytes for environmental biosensors. Systems have been developed for de-teeting organophosphate eompounds, several commercial herbi-cides, organic pollutants, and heavy metals. " ... 

The use of cyclic voltammetry has already been mentioned in the characterizations of nickel(II) complexes with nitrogen- and phosphorus-donor ligands and of ruthenium(II) terpyridine bipyridine complexes with a phosphorus(III) ligand.Similarly, it has been used in the characterization of bis(diphenylphosphinomethyl)amino ligands and their Ni(II) and Pd(II) complexes. " A novel electrochemical sensor for detection of Dimethoate insecticide, and other similar organophosphates (OPs), based on a thin film-imprinted polymer, has been produced using electrodeposition of silver nanoparticles and electropolymerisation controlled by cyclic voltammetry scans " and more details are given later under sensors and biosensors. 

Pesticides are another important group of pollutants that can be detected by fiber-optic chemical sensors. Since pesticides are designed to interact with biological molecules, fiber-optic biosensors are mostly used for their detection. One example is the detection of organophosphate and carbamate pesticides by monitoring their inhibition effect on the enzymatic reaction of acetylcholinesterase (AChE) with its substrate, acetylcholine. The enzyme is coimmobilized at the distal end of the fiber together with... 

Redox mediators have been used in this case for cathodic detection. An amperometric sensor for choline based on electron transfer between horseradish peroxidase and a redox polymer was described. Amperometric biosensors based on acetylcholinesterase or butyrylcholinesterase were used for the kinetic determination of organophosphate and carbamate pesticides. 

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