Organophosphorous pesticides/herbicide

Accelerated solvent extraction is a new technique for the extraction of a range of organic pollutants from soils and related material. The technique is based on the use of a solvent or combination of solvents to extract organic pollutants at elevated pressure and temperature from a solid matrix. The range of organic pollutants for which the technique is proposed includes semi volatile compounds, organochlorine pesticides, organophosphorous pesticides, chlorinated herbicides, polychlorinated biphenyls and polycyclic aromatic hydrocarbons [66-69]. 

On-line SPE via valve-switching techniques, pioneered by the group of Brinkman [80], is frequently used in the enviroiunental analysis of aqueous samples, as it enables the rapid treatment of large samples. The precolumn enables selective sorption of the analytes, removal of hydrophihc interferences, and significant analyte preconcentration. In most cases, either 1-10 mm x 2-4.6 mm ID SPE cartridges packed with 30-50 pm ID particles are used. Typical applications of on-hne SPE-LC-MS are the determination of acidic herbicides [41], sidfonylureas [49], and organophosphorous pesticides [30]. Instead of SPE cartridges, Empore disks can be used on-line as well [79]. 

Phenols of enviromnental interest are derived from a wide variety of industrial sources, or present as biodegradation products of humic substances, tannins, and lignins, and as degradation products of many chlorinated phenoxyacid herbicides and organophosphorous pesticides. Phenols, especially chlorophenols, are persistent, and toxic at a few pg/1. Therefore, phenols are hsted at the US-EPA hst of priority pollutants and the EU Directive 76/464/EEC as dangerous substances. The samples to be analysed can be surface waters or industrial effluents. 

There are many studies available concerning the characterization of interface and ionization performance for the thermospray LC-MS analysis of pesticides, herbicides and insecticides, the improvement of detection limits and information content of the mass spectra. Compound classes most frequently studied are the carbamates, organophosphorous pesticides, triazine and phenylurea herbicides, chlorinated phenoxy acetic acids, and sulphonylureas. 

Most of the common pesticides used now and in the past have also been found in the atmosphere, including DDT, toxaphene, dieldrin, heptachlor, organophosphorous insecticides, triazine herbicides, alachlor and metolachlor. These airborne pesticides return to the earth with rainfall to further contribute to water contamination. A recent... 

In agriculture, phenolic compounds are used as pesticides (Figure 1) and can also form from the degradation of chlorinated phenoxycarboxylic acids and organophosphorous insecticides". The herbicide DNOC sorption in a sandy aquifer (Denmark) has been reported ". 

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