Organophosphorus pesticides extraction

Recoveries (%) and Quantification Limits (LQ) of Organophosphorus Pesticides Extracted from Different Types of Water Sample Using SPE Cartridges with Different Sorbents... 

Kumaran, S. andMorita, M. (1995) Application of a cholinesterase biosensor to screen for organophosphorus pesticides extracted from soil. Talanta, 42 (4), 649-655. 

In 1994, Nam and King (68) developed a SFE/SFC/GC instrumentation system for the quantitative analysis of organochlorine and organophosphorus pesticide residues in fatty food samples (chicken fat, ground beef and lard). In this way, SFC was used as an on-line clean-up step to remove extracted material. The fraction containing pesticide residues is then diverted and analysed by GC. 

Methyl parathion was determined in dog and human serum using a benzene extraction procedure followed by GC/FID detection (Braeckman et al. 1980, 1983 DePotter et al. 1978). An alkali flame FID (nitrogen-phosphorus) detector increased the specificity of FID for the organophosphorus pesticides. The detection limit was in the low ppb (pg/L). In a comparison of rat blood and brain tissue samples analyzed by both GC/FPD and GC/FID, Gabica et al. (1971) found that GC/FPD provided better specificity. The minimum detectable level for both techniques was 3.0 ppb, but GC/FPD was more selective. The EPA-recommended method for analysis of low levels (<0.1 ppm) of methyl parathion in tissue, blood, and urine is GC/FPD for phosphorus (EPA 1980d). Methyl parathion is not thermally stable above 120 °C (Keith and Walters 1985). 

The use of SPE with porous materials such as alumina, diatomaceous earth, Horisil and silica for the cleanup of fat-soluble organochlorine pesticides in fatty foods such as meat, flsh, shellfish, milk and vegetable oils has been well documented. The choice of elution solvents is critical because relatively small amounts of lipid in the final extract can cause rapid deterioration of GC capillary columns and also contaminate the gas chromatograph. A number of workers have used a porous material in tandem with Cig to effect an improved cleanup.Di Mucchio employed a multicartridge system comprising Extrelut, silica and Cig to extract organophosphorus pesticides from oils and fatty extracts. Relatively few literature applications include the pyrethroids, but Ramesh and Balasubramanian reported a simple carbon-based SPE method for the analysis of pyrethroids in vegetable oil. 

Garcia-Valcarcel AI, Tadeo JL (2009) A combination of ultrasonic assisted extraction with LC-MS/MS for the determination of organophosphorus pesticides in sludge. Anal Chim Acta 641 (1—2) 117—123... 

Lacorte S. and Barceld D., 1995. Determination of organophosphorus pesticides and their transformation products in river waters by automated online solid-phase extraction followed by thermospray liquid chromatography. J Chromatogr A 712 103. 

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],... 

Application of supercritical fluid extraction (SFE) for selective isolation of organophosphorus pesticides from a real-world matrix (wheat flour) (Kim et al., 1998). 

A snpercritical flnid extraction (SEE) method for the determination in strawberries of a number of commonly used organochlorine insecticides, organophosphorus pesticides, and dichloroaniUde fungicides (Pearce et al., 1997). 

SFE also would appear to have utility in sample preparation methods. Lopez-Avila et al. (1992) applied SFE to the recovery of a variety of analytes, including organophosphorus pesticides, from solid matrices. The unoptimized extraction from sand gave a recovery of 54% for diazinon. Supercritical trifluoromethane has been shown to extract diazinon from glass beads with a recovery of 86% (Hillmann and Bachmann 1995). Organophosphorus pesticides have also been recovered from Tenax-GC, an adsorbent used to collect diazinon during air sampling, and analyzed directly by GC (Raymer and Velez... 

Kwakman PJM, Vreuls JJ, Brinkman UAT, et al. 1992. Determination of organophosphorus pesticides in aqueous samples by on-line membrane disk extraction and capillary gas chromatography. Chromatographia 34 41-47. 

A multiresidue method for analyzing 28 common organophosphorus pesticides and three of their main metabolites (paraoxon-ethyl, paraoxon-methyl, and malaoxon) in a variety of crop samples has been developed (59). The use of LC-DAD techniques allowed identification of both organophosphorus pesticides and metabolites by means of standard and spectral comparisons, respectively. A typical chromatogram for fortified apple extract is shown in Figure 4. 

S Lacorte, C Molina, D Barcelo. Temperature and extraction voltage effect on fragmentation of organophosphorus pesticides in liquid chromatography atmospheric pressure chemical ionization mass spectrometry. J Chromatogr A 795 13-26, 1998. 

S Lacorte, D Barcelo. Improvements in the determination of organophosphorus pesticides in ground and wastewater samples from interlaboratory studies by automated on-line liquid-solid extraction followed by liquid chromatography diode array detection. J Chromatogr A 725 85-92, 1996. 

S Lacorte, D Barcelo. Determination of part per trillion levels of organophosphorus pesticides in groundwater by automated on-line solid-phase extraction followed by thermospray liquid chromatography mass spectrometry. Anal Chem 68 2464 -2478, 1998. 

A Lagana, G D Ascenzo, G Fago, A Marino. Determination of organophosphorus pesticides and metabolites in crops by solid phase extraction followed by liquid chromatography/diode array detection. Chromatographia 46 256-264, 1997. 

A Farran, J De Pablo, S Hernandez. Continuous-flow extraction of organophosphorus pesticides coupled on-line with high-performance liquid chromatography. Anal Chim Acta 212 123-131, 1988. 

C Molina, P Grasso, E Benfenati, D Barcelo. Automated sample preparation with extraction columns followed by liquid chromatography-ionspray mass spectrometry. Interferences, determination and degradation of polar organophosphorus pesticides in water samples. J Chromatogr A 737 47-58, 1996. 

Applications of supercritical fluid extraction and headspace analysis are, however, now creeping in. Thus supercritical fluid extraction with carbon dioxide-methanol has been used to extract 2,4-chlorophenol from crops [231 ], sulfonylurea herbicides from plants [161], and organophosphorus pesticides from fruit and vegetables [226]. 

The extract should be then injected onto the GC column for GC or GC/MS analysis. If internal standard calibration is performed, spike three or more internal standards into the sample extract. Any organophosphorus pesticides whose analysis is not required or which is not found to be present in the screening test may be used as an internal standard. The chromatographic columns and conditions are presented below ... 

Organophosphorus pesticides SW-846 3510/8141 SW-846 3520/8141 One liter amber glass, PTFE-lined lid 1000 ml 2 to 6°C 7 days for extraction, 40 days for analysis... 

Lacorte, S., N. Ehresmann, and D. Barcelo. 1995. Stability of organophosphorus pesticides on disposable solid-phase extraction precolumns. Environ. Sci. Technol. 29 2834—2841. 

Lacorte and Barcelo [36] have described a procedure for the determination of nanogram per litre levels of organophosphorus pesticides in ground waters based on automated online liquid-solid extraction followed by liquid chromatography. The detection used on the liquid chromatograph is an atmospheric pressure chemical ionisation mass spectrometer using negative and positive ion modes of operation. 

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