Solid-phase extraction pesticide residues

The need to understand the fate of pesticides in the environment has necessitated the development of analytical methods for the determination of residues in environmental media. Adoption of methods utilizing instrumentation such as gas chro-matography/mass spectrometry (GC/MS), liquid chromatography/mass spectrometry (LC/MS), liquid chromatography/tandem mass spectrometry (LC/MS/MS), or enzyme-linked immunosorbent assay (ELISA) has allowed the detection of minute amounts of pesticides and their degradation products in environmental samples. Sample preparation techniques such as solid-phase extraction (SPE), accelerated solvent extraction (ASE), or solid-phase microextraction (SPME) have also been important in the development of more reliable and sensitive analytical methods. 

The development of solid-phase extraction (SPE) absorbents such as silica gel, alumina and Florisil tremendously aided in the purification or cleanup of pesticide residues from water. 

Manes J, Font G, Pico Y. 1993. Evaluation of a solid-phase extraction system for determining pesticide residues in milk. J Chromatog 642 195-204. 

G Font, J Manes, JC Molt6, Y Pico. Solid-phase extraction in multi-residue pesticide analysis of water. J Chromatogr 642 135-161, 1993. 

JJ Jimenez, JL Bernal, MJ del Nozal, JM Rivera. Determination of pesticide residues in waters from small loughs by solid-phase extraction and combined use of gas chromatography with electron-capture and nitrogen-phosphorus detection and high-performance liquid chromatography with diode array detection. J Chromatogr A 289-300, 1997. 

J Slobodnik, AC Hogenboom, JJ Vreuls, JA Rontree, BLM van Baar, WM A Niessen, UAT Brinkman. Trace-level determination of pesticide residues using on-line solid-phase extraction-column liquid chromatography with atmospheric pressure ionization mass spectrometric and tandem mass spectrometric detection. J Chromatogr A 741 59-74, 1996. 

Albanis, T.A. and D.G. Hela (1995). Multi-residue pesticide analysis in environmental water samples using solid-phase extraction discs and gas chromatography with flame thermionic and mass-selective detection. J. of Chromatogr. A, 707 283-292. 

The solvent extracts can be cleaned up by traditional column chromatography or by solid-phase extraction cartridges. This is a common cleanup method that is widely used in biological, clinical, and environmental sample preparation. More details are presented in Chapter 2. Some examples include the cleanup of pesticide residues and chlorinated hydrocarbons, the separation of nitrogen compounds from hydrocarbons, the separation of aromatic compounds from an aliphatic-aromatic mixture, and similar applications for use with fats, oils, and waxes. This approach provides efficient cleanup of steroids, esters, ketones, glycerides, alkaloids, and carbohydrates as well. Cations, anions, metals, and inorganic compounds are also candidates for this method [7],... 

Anastassiades, M., Lehotay, S.J., Stajnhaher, D., Schenck, F.J. Fast and easy multrresidue method employing acetonitrile extraction/partitioning and dispersive solid-phase extraction for the determination of pesticide residues in produce. J. AOAC InL 86(2), 412-431 (2003)... 

Pesticides are extracted from grapes with acetonitrile using a singlephase extraction followed by liquid-liquid partitioning formed by addition of MgS04 and NaCl. Removal of residual water and clean up are performed simultaneously by using dispersive solid-phase extraction. The pesticide extract was analyzed by GC/MS. 

The analysis of food contaminants, in particular any toxic or biologically active residue, is important for public health or quality control reasons.19 Examples are mycotoxins (aflatoxins) and pesticide and drug residues. Sample preparation is typically elaborate and might involve deproteinization, solvent extraction, and clean-up via solid-phase extraction (SPE).The use of highly sensitive and specific LC/MS/MS is increasing and has simplified some of the sample preparation procedures. 

Albanis, T. A., Hela, D. G., Sakellarides, T. M., and Konstantinou, I. K., Monitoring of pesticide residues and their metabolites in surface and underground water of Imathia (N. Greece) by means of solid-phase extraction disks and gas chromatography, J. Chromatogr. A, 823, 59-71, 1998. 

Kuivinen. J., and Bengi.s.son, S. (2(K12). Solid-phase extraction and dean up of organophasphorus pesticide residues in bovine muscle with gas chromatographic detection. J. Chromatogr. Sci. 40.392-396. 

In the field of pesticide residues in food, CE continues to gain ground and garner significant attention. However, one of the main drawbacks of CE is its low sensitivity in the monitoring of pesticide residue. Therefore, the use of different preconcentration strategies before the separation [e.g solid-phase extraction (SPE), liquid-liquid extraction, etc.] or different stacking procedures in... 

M. Molina, D. Perez-Bendito and M. SUva, Multi-residue analysis of A-methylcarbamate pesticides and their hydrolytic metabolites in enviroimiental waters by use of solid-phase extraction and micellar electrokinetic chromatography, Electrophoresis, 20, 3439-3449, 1999. 

Extraction of pesticide residues from liquid samples can be performed using a solid sorbent material. Currently available sorbent extraction techniques include (1) solid-phase extraction (SPE), (2) solid-phase microextraction (SPME), and (3) stir-bar sorptive extraction (SBSE). In the case of solid samples, a liquid extraction of pesticide residues (transfer into a solution) usually precedes the sorption step thus, it should be considered rather as a clean-up than an extraction. Matrix solid-phase dispersion (MSPD) represents a unique SPE approach that combines extraction and clean-up of solid or semisolid food samples in one step. In MSPD, the sample is mixed with a sorbent (Florisil, Cig, Cg) that serves as a solid support in sample disruption and dispersion. The resulting mix is packed into a column from which the analytes are eluted while separated matrix components are retained by the sorbent. The main drawbacks of this approach comprise rather small sample sizes ( 0.5g) and a relatively high consumption of expensive sorbents. 

See alsa Chromatography Multidimensional Techniques. Environmental Analysis. Extraction Solid-Phase Extraction. Food and Nutritional Analysis Sample Preparation Contaminants Pesticide Residues. Forensic Sciences Drug Screening in Sport Illicit Drugs. Herbicides. Liquid Chromatography Instrumentation Clinical Applications Food Applications. Mass Spectrometry Peptides and Proteins. Pesticides. Pharmaceutical Analysis Sample Preparation. Proteomics. Sample Handling Automated Sample Preparation. Water Analysis Organic Compounds. 

Solid-phase extraction (SPE) using small, disposable cartridges, columns, or disks is employed for isolation and cleanup of pesticides from water and other samples prior to TLC analysis, especially using reversed-phase (RP) octa-decyl (C-18) bonded silica gel phases. Microwave-assisted extraction (MAE) is a time- and solvent-saving method for removing residues from samples such as soils. Supercritical fluid extraction (SEE) has been used for sample preparation in the screening of pesticide-contaminated soil by conventional TLC and automated multiple development (AMD). Ultrasonic solvent extraction (USE) and videodensitometry have been combined for quantification of pesticides in sod. Matrix solid-phase dispersion (MSPD) with TLC and GC has been used to determine diazinon and ethion in nuts. 

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