Solid phase micro extraction applications

Grassi, P., J. Novak, H. Steinlesberger, and Ch. Franz, 2004. A direct liquid, non-equilibrium solid-phase micro-extraction application for analysing chemical variation of single peltate trichomes on leaves of Salvia officinalis. Pl tochenLAr., 15 198-203. 

Applications Coupling of solid-phase micro-extraction and a micro-GC (separation times of 15 sec) is suitable for rapid field screening and potentially useful for process analysis. Odours at ppt level can be analysed by... 

Complex matrixes typically cannot be analysed directly to obtain the selectivity and sensitivity required for most trace analysis applications. To circumvent this problem, solid-phase micro extraction techniques were used to preconcentrate analytes selectively prior to gas chromatography/ion trap mass spectrometry analysis. 

In environmental analytical applications where analyte concentrations, e.g. surfactants or their metabolites, are quite low, extraction and concentration steps become essential. Solid phase extraction (SPE) with cartridges, disks or SPME fibres (solid phase micro extraction) because of its good variety of SP materials available has become the method of choice for the analysis of surfactants in water samples in combination with FIA as well as LC—MS analysis. SPE followed by sequential selective elution provides far-reaching pre-separations if eluents with different polarities and their mixtures are applied. The compounds under these conditions are separated in the MS spectrometer by their m/z ratios providing an overview of the ionisable compounds contained in a sample. Identification in the sense it has been mentioned before, however, requires the generation of fragments. 

C.-W. Whang, in J. Pawliszyn, ed., Applications of Solid Phase Micro-extraction, Royal Society of Chemistry, Cambridge, 1999, pp. 22-40. 

Solid-phase extraction devices and applications are evolving rapidly, and novel techniques that stretch the classical definition of SPE are becoming routine. Pawliszyn introduced solid-phase micro extraction (SPME) in 1989,5,14 and a commercial apparatus is available from Supelco (Bellefonte, PA). The SPME apparatus is merely a modified syringe that houses a fused silica optical fiber coated with an immobilized polymer film. The fiber can be exposed for extraction and then retracted for insertion or removal from the sample vial or instrument. Both manual and autosampler devices are available and each can be adjusted for proper fiber depth. Several coatings are available with varying thickness including polydimethylsiloxane, polyacrylate, polydimethylsiloxane/divinylbenzene, and carbowax/divinylben-zene. In contrast to SPE, which is an exhaustive extraction approach, SPME will extract only a fraction of an available analyte, hence it is not suitable for the isolation of impurities and degradants in most applications.15... 

In this introductory book chapter, several modem extraction techniques will be described, including supercritical fluid extraction, pressurized liquid extraction, pressurized hot Avater extraction, microwave assisted extraction, membrane-assisted solvent extraction, solid phase micro extraction and stir-bar sorptive extraction. These are techniques that meet many of today s requirements in terms of environmental sustainability, speed and automation. Basic principles of operation as well as method optimization will be discussed and compared for the different techniques. Both analytical and industrial applications will be discussed, together with commercial instruments available on the market. Key references will be given, and conclusions regarding applicability of the different techniques with respect to sample e, target-molecules and analytical vs. large-scale applications. 

Even though the interest in microwave-assisted extraction (MAE) has increased during the last 10 years, this technique has not been utilized much in food and feed applications. Only a few papers can be found with the combination of POPs and food/feed samples. This may be because MAE applications frequently require laborious and tedious clean-up of the extracts before final analysis. In some cases, only a simple filtration or centrifugation may be sufficient to separate the solid matrix from the extract but since MAE most often is more exhaustive than selective, extensive clean-up procedures based on for example solid-phase extraction is commonly needed for removal of interfering compounds (73-75). Other techniques that have been used for clean-up of MAE extracts are gel permeation chromatography (75), solid-phase micro extraction (77, 78), and liquid-liquid extraction (79). 

An interesting application of microwave energy for the preparation of standard gas of VOC was described by Xiong and Pawhszyn." With a domestic microwave oven the authors developed a simple, powerful, rapid, accurate and safe procedure for preparation of VOC/semiVOC standard gas. Solid-phase micro extraction combined with GC was used for the gas analysis. Worth mentioning here is that because of the specific way in which microwaves interact with matter, an appropriate amount of water was introduced during the preparation of the gas mixtures since the molecules of the studied VOCs are weakly polar or nonpolar and therefore very poor absorbers of microwave energy. 

Nilsson T. Larsen T.O., Montarella L. and Madisen J.O. (1996) Application of headspace solid-phase micro-extraction for the analysis of volatile metabolites emitted by Penicillium species. J. Microbiol. Methods, 25, 245-255. 

Solid Phase Micro-extraction Solid phase micro-extraction (SPME) was developed in 1989 by Pawliszyn and coworkers °" ° as a simple and effective adsorption/adsorption and desorption technique that eliminates the need for solvents. Applications of SPME in the analysis of drugs have been reviewed, as well as the possibilities of interfacing SPME with HPLC. ° SPME... 

Application of an Automated Headspace Solid Phase Micro-Extraction for the GC-MS Detection and Quantification of Reductive Sulfur Compounds in Wines... 

Application of an Automated Headspace Solid Phase Micro-Extraction... 

Application of solid-phase micro extraction to the analysis of volatile compounds in virgin olive oils from five new cultivars. Food Chem. 102 850-856. 

Llompart, M., K. Li, and M. F. Fingas. 1997a. The Application of Solid Phase Micro Extraction (SPME) for Spill Emergency Work, Part 1 HS-SPME Analysis of Volatiles and Semi-volatiles in Soil, in Proceedings of the Fourteenth Technical Seminar on Chemical Spills, Environment Canada, Ottawa, ON, pp. 83-91. 

A new technique, which is applicable for sampling in air and liquids or in the headspace above a liquid or a solid sample, is solid-phase micro-extraction (SPME). The mechanism of SPME, which has been developed by Pawliszyn et al. 1225], [226], is based on the partition equilibrium of the analytes between the sample or the head-space above the sample, respectively, and a fused silica fiber coated with a suitable stationary phase. The amount of analyte extracted by the fiber is proportional to the initial analyte concentration in the sample and depends on the type of fiber. After sampling, the fiber can be thermally desorbed directly into the injector of a gas chromatograph. SPME combines sampling, analyte enrichment, matrix separation, and sample introduction within one step [226]. Since its development, this innovative technique has found widespread use in environmental analysis. It has, for example, been applied in the determination of volatile organic compounds [227], 228]. phenols [229],... 

The discussion of headspace methods for blood alcohol and solid-phase micro extraction (SPME) in Section 4.2 introduced the concept of creating an enriched head-space above a sample. Headspace methods may be passive or active and may involve heating the sample. Dynamic headspace (DHS) methods, used in arson analyses, exploit the equilibrium at the liquid-sample interface by sweeping tire headspace with a constant stream of gas, usually helium. DHS is also referred to as purge-and-trap (FT), allhough the latter can also mean a specific t) of sample preconcentrator used in environmental analysis. The trap material can be thermally desorbed or desorbed wifii a solvent. The thermal method is preferred, but is not always possible. The choice of trapping or sorbent materials depends on fire application arson typically requires charcoal or charcoal combinations. 

Up to now, most efforts have been directed towards the preparation of uniformly sized spherical MIP particles in the micrometre range. This is the obvious consequence of the need for this kind of materials as fillers for high-performance chromatographic columns, capillaries for electrophoresis, cartridges for solid-phase extractions and other applications requiring selective stationary phases. Additionally though, strategies for the preparation of other more sophisticated MIP forms, such as membranes, (nano)monoliths, films, micro- and nanostructured surfaces etc. 

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