Organochlorine compounds Organophosphorus pesticides

This method is applicable to the extraction of seml-volatile organic compounds, organophosphorus pesticides, organochlorine pesticides, chlorinated herbicides, PCBs and PCDDs/PCDFs, which may then be analysed by a variety of chromatographic procedures. 

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 semivolatile compounds, organochlorine pesticides, organophosphorus pesticides, chlorinated herbicides, polychlorinated biphenyls and polycyclic aromatic hydrocarbons [53-56],... 

Pesticides are also a major source of concern as water and soil pollutants. Because of their stability and persistence, the most hazardous pesticides are the organochlorine compounds such as DDT, aldrin, dieldrin, and chlordane. Persistent pesticides can accumulate in food chains for example, shrimp and fish can concentrate some pesticides as much as 1000- to 10,000-fold. This bioaccumulation has been well documented with the pesticide DDT, which is now banned in many parts of the world. In contrast to the persistent insecticides, the organophosphorus (OP) pesticides, such as malathion, and the carbamates, such as carbaryl, are short-lived and generally persist for only a few weeks to a few months. Thus these compounds do not usually present as serious a problem as the earlier insecticides. Herbicides, because of the large quantity used, are also of concern as potential toxic pollutants. Pesticides are discussed in more detail in Chapter 5. 

In Figure 3, Bowman and Beroza s extraction p-values obtained from different pairs of immiscible solvents are plotted (10). The degree of correspondence for the p-values of these compounds—organochlorine and organophosphorus insecticides and other pesticides— from one pair of solvents to another is clearly featured. The additional independent evidence for identity gained by obtaining a second p-value is very small. 

In general, the nature of the analyte determines the choice of stationary phase. For example, for the separation of organochlorine and pyrethroid pesticides, a nonpolar stationary phase such as DB-1 (or OV-1) is recommended. For the separation of somewhat more polar compounds, such as organophosphorus compounds, OV-17 (or DB-1701) can be applied. In addition, for confirmation purposes, the use of two columns with distinct stationary-phase polarities (e.g., DB-1 and DB-1701) is certainly required. A polar stationary phase (e.g., DB-wax) is suitable for the more polar compounds such as methamidofos, but its application to some detection modes is limited due to stationary-phase bleeding. 

In 1994 Lopez-Avila et al., published their work to expand the use of MAE to 187 volatile and semivolatile organic compounds from soils. The compounds included polyaromatic compounds, phenols, organochlorine pesticides and organophosphorus pesticides. MAE uses microwaves that can easily penetrate into the sample pores causing the solvent trapped in the pores to heat evenly and rapidly. In contrast to conventional heating MAE is a promising technique because ... 

A wide variety of pesticides including organochlorine and organophosphorus compounds, triazines, herbicides, and imidazolinones have been extracted using microwaves, with recoveries 100% in most cases. 

A wide range of pesticides including organochlorine [216,217] and organophosphorus compounds [218], triazines [219-222], herbicides [43,62] and imidazolinones [223] have been extracted with the aid of microwaves, with recoveries close to 100% in most cases. 

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