Solid-phase microextraction quantitative analysis

Principles and Characteristics As mentioned already (Section 3.5.2) solid-phase microextraction involves the use of a micro-fibre which is exposed to the analyte(s) for a prespecified time. GC-MS is an ideal detector after SPME extraction/injection for both qualitative and quantitative analysis. For SPME-GC analysis, the fibre is forced into the chromatography capillary injector, where the entire extraction is desorbed. A high linear flow-rate of the carrier gas along the fibre is essential to ensure complete desorption of the analytes. Because no solvent is injected, and the analytes are rapidly desorbed on to the column, minimum detection limits are improved and resolution is maintained. Online coupling of conventional fibre-based SPME coupled with GC is now becoming routine. Automated SPME takes the sample directly from bottle to gas chromatograph. Split/splitless, on-column and PTV injection are compatible with SPME. SPME can also be used very effectively for sample introduction to fast GC systems, provided that a dedicated injector is used for this purpose [69,70],... 

D. Zabaras, S. G. Wyllie, Quantitative analysis of terpenoids in the gas phase using headspace solid phase microextraction (HS SPME), Flavour Fragr. J., 16, 411 416 (2001). 

J. Ai, Headspace solid phase microextraction. Dynamics and quantitative analysis before reaching a partition equilibrium, Anal. Chem., 69, 3260 (1997). 

Both HPLC and GC-MS were employed for the separation, identification and quantitation of the decomposition products of indigo and indigo carmine. The chemical structures of the dyes are shown in Fig. 3.73. Carboxylic acids were preconcentrated before HPLC analysis either by ion-exchange SPE or by solid-phase microextraction. HPLC measurements were performed in a Sarasep column (300 X 7.8 mm i.d.) using 5 mM H2S04 at a flow rate of 0.7 ml/min. Analytes were detected at 215 nm. The main intermediates formed during the photocatalytic decomposition are compiled in Table 3.26. The results demonstrated that... 

J. J. Langenfeld. S. B. Hawthorne, and D. J. Miller. Quantitative Analysis of Fuel-Related Hydrocarbons in Surface Water and Wastewater by Solid-Phase Microextraction Anal. Chem. 1996,68, 144. 

Ai, J. 1997. Solid phase microextraction for quantitative analysis in nonequilibrium situations. Anal. Chem. 69 1230-1236. 

Beltran, J., Serrano, E., Lopez, F.J., Pemga, A., Valcarcel, M., Rosello, S. Comparison of two quantitative GC-MS methods for analysis of tomato aroma based on purge-and-trap and on solid-phase microextraction. Anal. Bioanal. Chem. 385, 1255-1264 (2006)... 

Nilsson, T, Ferrari, R., and Facchetti, S., Interlaboratory Studies for the Validation of Solid-phase Microextraction for the Quantitative Analysis of Volatile Organic Compounds in Aqueous Samples, Analytica Chimica Acta 356,1997, 113-123. 

Giordano, L., Calabrese, R., Davoli, E., and Rotilio, D. (2003). Quantitative analysis of 2-furfural and 5-methylfurfural in different Italian vinegars by headspace solid-phase microextraction coupled to gas chromatography-mass spectrometry using isotope dilution. J. Chromatogr. A 1017,141-149. 

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. 

Tuduri, L., Desauziers, V., and Fanlo, J. L., Dynamic versus static sampling for the quantitative analysis of volatile organic compounds in air with polydimethylsiloxane-carboxen solid-phase microextraction hbers, J. Chromatogr. A, 963, 49-56, 2002. 

Used as preservatives in many topical pharmaceutical products, paraben esters have been found to exhibit estrogenic effects that have been linked to breast cancer. This has led to requiranents for their rapid and quantitative detection. Traditional methods of analysis are slow and tedious. For gas chromatographic methods, derivatization as silyl- or fluoroacetyl derivatives followed by extraction and sample cleanup complicate the process, while liquid chromatographic methods require extraction and long chromatographic run times. To increase speed and decrease complexity, solid phase microextraction with ion mobility spectrometry (SPME-IMS) was used for the determination of parabens in pharmaceutical formulations. ... 

While open tubular (OT) columns are the most popular type, both open tubular and packed columns are treated throughout, and their advantages, disadvantages, and applications are contrasted. In addition, special chapters are devoted to each type of column. Chapter 2 introduces the basic instrumentation and Chapter 7 elaborates on detectors. Other chapters cover stationary phases (Chapter 4), qualitative and quantitative analysis (Chapter 8), programmed temperature (Chapter 9), and troubleshooting (Chapter 11). Chapter 10 briefly covers the important special topics of GC-MS, derivatization, chiral analysis, headspace sampling, and solid phase microextraction (SPME) for GC analysis. 

Caffeine can be extracted from aqueous solution by solid-phase microextraction (Section 22-4). In this procedure, a fused-silica (Si02) fiber coated with a polymer is dipped into the liquid and solutes from the liquid distribute themselves between the polymer phase and the liquid. Then the fiber is withdrawn from the liquid and heated in the port of a gas chromatograph. Solutes evaporate from the polymer and are carried into the column. Suggest a procedure for the quantitative analysis of caffeine in coffee by using solid-phase microextraction with a Cvcaffeine internal standard. 

Multiple solid phase microextraction in a nonequilibrium situation application in quantitative analysis of chlorophenols and chloroanisoles related to cork taint in wine. Journal of Chromatography A, 1089,31-38. 

Nilsson, T. Ferrari, R. Facchetti, S. Inter-laboratory studies for the validation of solid-phase microextraction for the quantitative analysis of volatile organic compounds in aqueous samples. Analytica Chimica Acta 1997, 356 (2-3), 113-123. 

Also in solid-phase microextraction (SPME) analytes are typically not extfacted quantitatively from the matrix. However, when partition equilibrium is reached, the extracted amount of an analyte is proportional to its initial concentration in the sample matrix phase. As indicated by Ai [33], application of SPME for quantitative analysis is feasible also when the partition equilibrium is not attained. Pawliszyn [34] has reviewed the quantitative aspects of SPME. Provided proper calibration strategies are followed, SPME can yield quantitative data and excellent precision, reproducibility and linearity (detection limits of 15 ng/L). In terms of precision, linearity and sensitivity SPME equals HS techniques. 

Solid-phase microextraction has been investigated for the analysis of 2,4,6-trichloroanisole, a cork taint compound, in wine samples [16]. This solvent-free procedure was coupled to GC-MS under selective ion monitoring (SIM) conditions using a fully deuterated internal standard ([ H5]trichloroanisole) for quantitative purposes. The SPME-GC-MS method was demonstrated to be selective, precise, and sensitive with a 5 ng limit of quantification. 

Many analytical techniques have been used for the quantitation of VOC in water and soil, including liquid-liquid microextraction (LLME), solid phase microextraction (SPME) and P T. Automated static headspace analysis offers the... 

Solid phase microextraction, i.e., extraction of an analyte onto the surface of a small fiber inserted into an aqueous sample, was demonstrated for OPE isolation using an experimental PEG-coated fiber. The fiber was then placed in a specially modified HPLC injection port for quantitative analysis (108). Concentration of AE using a fiber coated with silicone/divinylbenzene polymer has also been demonstrated (109). 

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