Solid-phase microextraction method development

Roberts, D.D., Pollien, P., and Milo, C. Solid-phase microextraction method development for headspace analysis of volatile flavor compounds, /. Agric. Food Chem., 48(6) 2430-2437, 2000. 

Diaz A, Ventura F, Galceran MT (2002) Development of a solid-phase microextraction method for the determination of short-ethoxy-chain nonylphenols and their brominated analogs in raw and treated water. J Chromatogr A 963 159-167... 

Development and validation of a solid phase microextraction method for the determination of coumarin and safrole in foods. 

Similar biomimetic methods have been developed for assessing the (bio)avail-ability of organic chemicals in water, sediments, and soil (Mayer et al. 2003 Ter Laak et al. 2006). The main advantage of these nondepletion techniques, such as the solid-phase microextraction methods (SPMEs), is that they may be used without disturbing the chemical distribution in surface water or soils or sediments. 

Cioni, F., Bartolucd, G., Pieraccini, G., Meloni, S., and Moneti, G. (1999) Development of a solid phase microextraction method for detection of the use of banned azo dyes in coloured textiles and leather. Rapid Commun. Mass Spectrom., 13, 1833-1837. 

Several others techniques dealing with the injection problems have been developed. Among them the solid-phase microextraction method (SPME) and the full evaporation technique must be mentioned. According to Camarasu, the SPME technique seems to be very promising for RS determination in pharmaceuticals, with much better sensitivity than the static headspace technique. 

A recent method, still in development, for determining total 4-nitrophenol in the urine of persons exposed to methyl parathion is based on solid phase microextraction (SPME) and GC/MS previously, the method... 

A recent method, still in development, for determining total 4-nitrophenol in the urine of persons exposed to methyl parathion is based on solid phase microextraction (SPME) and GC/MS previously, the method has been used in the analysis of food and environmental samples (Guidotti et al. 1999). The method uses a solid phase microextraction fiber, is inserted into the urine sample that has been hydrolyzed with HCl at 50° C prior to mixing with distilled water and NaCl and then stirred (1,000 rpm). The fiber is left in the liquid for 30 minutes until a partitioning equilibrium is achieved, and then placed into the GC injector port to desorb. The method shows promise for use in determining exposures at low doses, as it is very sensitive. There is a need for additional development of this method, as the measurement of acetylcholinesterase, the enzyme inhibited by exposure to organophosphates such as methyl parathion, is not an effective indicator of low-dose exposures. 

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. 

A new, fast, sensitive, and solventless extraction technique was developed in order to analyze beer carbonyl compounds. The method was based on solid-phase microextraction with on-fiber derivatization. A derivatization agent, 0-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine (PFBOA), was absorbed onto a divinyl benzene/poly(dimethylsiloxane) 65- xm fiber and exposed to the headspace of a vial with a beer sample. Carbonyl compounds selectively reacted with PFBOA, and the oximes formed were desorbed into a gas chromatograph injection port and quantified by mass spectrometry. This method provided very high reproducibility and linearity When it was used for the analysis of aged beers, nine aldehydes were detected 2-methylpropanal, 2-methylbutanal, 3-methylbutanal, pentanal, hexanal, furfural, methional, phenylacetaldehyde, and (E)-2-nonenal. (107 words)... 

Solid-phase microextraction (SPME), a new solvent-free sample preparation technique, was invented by C. Arthur and J. Pawliszyn in 1990. This method was mainly applied for the extraction of volatile and semivolatile organic pollutants in water samples. However, since 1995, SPME has been developed to various biological samples, such as whole blood, plasma, urine, hair, and breath, in order to extract drags and poisons in forensic field. The main advantages of SPME are high sensitivity, solventless, small sample volume, simplicity, and rapidity (Liu et al., 1998). 

You need to decide the goal of an analysis before developing a chromatographic method. The key to successful chromatography is to have a clean sample. Solid-phase microextraction, purge and trap, and thermal desorption can isolate volatile components from complex matrices. After the sample preparation method has been chosen, the remaining decisions for method development are to select a detector, a column, and the injection method, in that order. 

Rancidity measurements are taken by determining the concentration of either the intermediate compounds, or the more stable end products. Peroxide values (PV), thiobarbituric acid (TBA) test, fatty acid analysis, GC volatile analysis, active oxygen method (AOM), and sensory analysis are just some of the methods currently used for this purpose. Peroxide values and TBA tests are two very common rancidity tests however, the actual point of rancidity is discretionary. Determinations based on intermediate compounds (PV) are limited because the same value can represent two different points on the rancidity curve, thus making interpretations difficult. For example, a low PV can represent a sample just starting to become rancid, as well as a sample that has developed an extreme rancid characteristic. The TBA test has similar limitations, in that TBA values are typically quadratic with increasing oxidation. Due to the stability of some of the end-products, headspace GC is a fast and reliable method for oxidation measurement. Headspace techniques include static, dynamic and solid-phase microextraction (SPME) methods. Hexanal, which is the end-product formed from the oxidation of Q-6 unsaturated fatty acids (linoleate), is often found to be a major compound in the volatile profile of food products, and is often chosen as an indicator of oxidation in meals, especially during the early oxidative changes (Shahidi, 1994). 

Zeng, E.Y., D. Tsukada, and D.W. Diehl. 2004. Development of solid-phase microextraction-based method for sampling of persistent chlorinated hydrocarbons in an urbanized coastal environment. Environ. Sci. Technol. 38 5737-5743. 

Z. Penton, Method development with solid phase microextraction, in S. A. Scheppers Wercinski, ed., Solid Phase Microextraction A Practical Guide, Marcel Dekker, New York, 1999, pp. 27-57. 

Solid-phase microextraction (SPME) is a relatively new method of sample introduction, developed by Pawliszyn and co-workers in 1989 [28,29] and... 

Kumar, A., Ashok, G., Malik, K., Kumar Tewary, D., Singh, B. A review on development of solid phase microextraction fibers by sol-gel methods and their applications. Anal. Chim. Acta 610, 1-14 (2008)... 

Recently, the method of gas chromatographic solid-phase microextraction (GC-SPME) has been developed (308-310). This method uses fibers coated with various polymers to extract volatile compounds from a food system. The method can be used in solid, liquid, and gaseous systems. It is fairly easy to evaluate volatile compounds by this analysis and to maintain consistent conditions. 

Solid-phase microextraction (SPME) was developed as an alternative to many other sample preparation methods because it uses virtually no solvents or complicated equipment. It is an adsorption/desorption device where the compounds of interest are adsorbed onto a fused-silica fiber. After a given time, the fiber is placed into a gas chromatograph (GC), where the compounds are thermally desorbed. SPME has recently been adapted for use in HPEC, where compounds that are adsorbed are desorbed using an appropriate solvent. 

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