Solid phase microextraction solventless technique

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). 

Solid-phase microextraction (SPME) is a fast and solventless modification of SPE techniques [20]. SPME involves the use of fiber (fused silica fiber or polymer-coated fused fiber) coated by an adsorbent. The method is applied for extraction of different kinds of both volatile and nonvolatile analytes from different kinds of media, which can be in liquid or gas phase. In the direct extraction mode, coated fiber is immersed in the sample for a defined time, until equilibrium between the sample matrix and the solid phase is reached. The analyte is transported by diffusion directly to the extracting phase. In the next stage, the compound of interest... 

Solid-phase microextraction (SPME) is a technique that was first reported by Louch et al. in 1991 (35). This is a sample preparation technique that has been applied to trace analysis methods such as the analysis of flavor components, residual solvents, pesticides, leaching packaging components, or any other volatile organic compounds. It is limited to gas chromatography methods because the sample must be desorbed by thermal means. A fused silica fiber that was previously coated with a liquid polymer film is exposed to an aqueous sample. After adsorption of the analyte onto the coated fiber is allowed to come to equilibrium, the fiber is withdrawn from the sample and placed directly into the heated injection port of a gas chromatograph. The heat causes desorption of the analyte and other components from the fiber and the mixture is quantitatively or qualitatively analyzed by GC. This preparation technique allows for selective and solventless GC injections. Selectivity and time to equilibration can be altered by changing the characteristics of the film coat. 

Shamsul Hairi, S., Yoshihiro, S., Yoshiaki, K., and Kiyokatsu, J., Solventless sample preparation procedure for organophosphorus pesticides analysis using solid-phase microextraction and online supercritical fluid extraction/high performance liquid chromatography technique. Anal. Chim. Acta, 433, 207-215, 2001. 

A solventless technique of solid-phase microextraction (SPME) has been also employed for HPLC determination of MC in a natural Microcystins sp. bloom in a freshwater, where three dominant MC variants MC-LR, -YR, and -RR were quantified. For this purpose a measuring system with commercial SPME-HPLC interface was employed. Microcystins were sorbed from acidified solutions using SPME fibers with carbowax/templated resin and polydi-methylsiloxane/divinylbenzene coating and desorbed at dynamic mode with HPLC eluent, which was used in isocratic elution mode and consisted of water and methanol with 0.05% TFA. For each toxin partition equilibrium was achieved within 60 min and example response obtained in SPME-HPLC system is shown in Fig. 6. The detection limits for all examined MC for 5 ml samples were reported at about 7 ppb. 

Solid-phase microextraction (SPME) is well documented with respect to its convenience and applicability to sampling volatiles and as an extraction technique to detect ignitable liquid residues when coupled with GCMS (185-188). Nonetheless, fire debris analysts have yet to widely adopt SPME as a viable alternative to the activated charcoal passive headspace technique. SPME is a simple, solventless extraction procedure in which a phase-coated fused-silica fiber is exposed to the headspace above the fire debris packaged in a closed container. A drawback to the procedure requires a rubber sleeve septum be placed at the opening of the container for maximum recovery of analytes. The technique has been applied successfully for the detection of flammable and combustible liquid residues on human skin (189). 

Solid-phase microextraction (SPME) appears to offer flavor and fragrance chemists significant benefits as an extraction/concentration technique prior to gas chromatography (GC) analysis. It is simple, rapid, solventless, and sensitive. Furthermore, it is less expensive to implement than purge-and-trap methods and many other sample preparation techniques that require specialized ancillary instrumentation. Before adapting a new extraction technology like SPME as a routine procedure, it is important to understand how it compares to the standard sample preparation techniques that have been used in the past. 

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