Surface waters organophosphorus compounds

Y. Pico, A. J. H. Louter, J. J. Vreuls and U. A. Th Brinkman, On-line trace-level enrichment gas chromatography of triazine herbicides, organophosphorus pesticides and organosulfur compounds from drinking and surface waters , Analyst 119 2025 -2031... 

In general, organophosphorus compounds show relatively low thermal stability. They decompose relatively quickly under the process conditions, either being converted to phosphorus pentoxide, or in the presence of water vapour to higher, condensed phosphoric acids. It is phosphorus compounds such as these which reach the surface of the catalyst. Most researchers have concluded that phosphorus poisoning is non-selective and can therefore additionally serve as a model for other non-selective poisons such as lead and zinc. Most researchers have... 

The use of a direct event for indication of analyte presence and concentration allow this detection technique to be used in real time. This, together with the broad nature of the detection protocols, makes the sensor system ideally suited for application as an early warning device. The surfaces can be used for repeated assays throughout their frmctional lifetimes and are exceptionally sensitive, with limits of detection for organophosphorus compounds below the current safe drinking water standards (75, 14, 17, 18, 44). In addition to detection of a variety of analytes in solution (70, 12-18), these enzyme based surfaces have been applied to the detection of GB vapor as well as gaseous carbon dioxide 16, 18). 

Irrigation and precipitation events result in the entry of organophosphorus insecticides into the hydrologic cycle. Organophosphorus compounds deposited on foliar surfaces, dissolved in soil water and sorbed to particles are mobilized and transported with surface runoff The main mobilization processes are discussed below. 

Frank R, Braun HE, Chapman N, et al. 1991b. Degradation of parent compounds of nine organophosphorus insecticides in Ontario surface and ground waters under controlled conditions. Bull Environ Contam Toxicol 47 374-380. 

A piezoelectric biosensor, for the detection of several organophosphorus pesticides was developed (Halamek et al., 2005). The sensor was based on the immobilization of a reversible inhibitor of cholinesterase on the surface of the sensor. The binding of AChE to this inhibitor was monitored with a mass-sensitive piezoelectric quartz crystal. In the presence of an inhibiting substance in the sample, the binding of the enzyme to the immobilized compound was reduced, and the decrease of mass change was proportional to the concentration of the analyte in the sample. This sensor was applied to the determination of pesticides in river water samples. 

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