Supported-phase microextraction

In the past decade, several novel solvent-based microextraction techniques have been developed and applied to environmental and biological analysis. Notable approaches are single-drop microextraction,147 small volume extraction in levitated drops,148 flow injection extraction,149 150 and microporous membrane- or supported liquid membrane-based two- or three-phase microextraction.125 151-153 The two- and three-phase microextraction techniques utilizing supported liquid membranes deposited in the pores of hollow fiber membranes are the most explored for analytes of wide ranging polarities in biomatrices. This discussion will be limited to these protocols. [Pg.35]

Bardstu, K.F., Ho, T.S., Rasmussen, K.E., Pedersen-Bjergaard, S. and Jonsson, J.A. (2007) Supported liquid membranes in hollow fiber liquid-phase microextraction (LPME) — Practical considerations in the three-phase mode. Journal of Separation Science, 30, 1364. [Pg.541]

Note SLM, supported liquid membrane (aq/org/aq) MMLLE, microporous membrane liquid-liquid extraction (aq/org) PME, polymer membrane extraction (aq/polymer/org) MESI, membrane extraction with sorbent interface (aq (or gas)/polymer/gas/sorbent) CFLME, continuous flow liquid membrane extraction (aq/org (in flow)/aq) LPME2, two-phase liquid phase microextraction in hoUow fibers (aq/org) LPME3, three-phase liquid phase microextraction in hollow fibers (aq/org/aq). [Pg.361]

FIGURE 13.3 Hollow-fiber devices for membrane extraction (a) hollow-fiber loops for equilibrium extraction. (Reprinted from Liu, J.-F., Jonsson, J.A., and Mayer, R, Equilibrium sampling through membranes of freely dissolved chlorophenols in water samples with hollow fiber supported liquid membrane, Anal. Chem., 77, 4800. Copyright 2005 American Chemical Society.) (b) Liquid-phase microextraction device... [Pg.380]

Bardstu KF, Ho TS, Rasmussen KE, Pedersen-Bjergaard S, Jonsson jA. Supported hquid membranes in hollow fiber liquid-phase microextraction (LPME). Practical considerations in the 3-phase mode. J Sep Sci 2007 30 1364-1370. [Pg.397]

Sorptive extraction techniques are based on the distribution equilibria between the sample matrix and a non-miscible liquid phase. Matrices are mostly aqueous and the non-miscible phase is often coated onto a solid support. Analytes are extracted from the matrix into the non-miscible extracting phase. Unlike adsorption techniques, where the analytes are bound to active sites on the surface, the total volume of extraction phase is important. Extraction of analytes depends on the partitioning coefficient of solutes between the phases (Ridgway et al., 2007). Two extraction techniques are commonly employed solid phase microextraction (SPME) and stir-bar sorptive extraction (SBSE). [Pg.123]

Solid-phase microextraction (SPME) was developed to address the need to facilitate rapid sample preparation both in the laboratory and onsite where the investigated system is located. In this technique, a small amount of extracting phase dispersed on a solid support is exposed to the sample for a well-defined period of time. In one approach, a partitioning equilibrium between the sample matrix and extraction phase is reached. In this case, convection conditions do not affect the amount extracted. In the second approach utilizing short time pre-equilibrium extraction, if convection/agitation is constant, the amount of analyte extracted is related to extraction time. Quantification can then be performed based on timed... [Pg.1214]

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. [Pg.1498]

Accelerated solvent extraction (ASE), focused microwave soxhiet extraction (FMSE), immuno affinity cleanup (im-Cu), liquid-liquid extraction (LLE), low-temperature lipid precipitation (LTLP), matrix solid-phase dispersion (MSPD), microwave-assisted extraction (MAE), nanofiltration (NF), pressurized fluid extraction (PEE), single drop microextraction (SOME), solid-phase extraction (SPE), solid-phase microextraction (SPME), steam distillation (SD), stir bar sorptive extraction (SBSE), surpercritical fluid extraction (SFE), subcritical fluid extraction (ScFE), supported liquid membrane extraction (SLME), ultra-sonication (US), size exclusion chromatography (SEC), liquid chromatography-fraction collection (LC)... [Pg.3600]

New progresses to establish LLE have been done in the past 10 years and is still under development. Examples of these include single-drop-liquid-phase microextraction (SD-LPME), LPME, and supported membrane extraction (SME). Single drop-LPME is based on a drop of organic solvent hanging at the end of a syringe needle. [Pg.637]

In liquid-phase microextraction (LPME), a liquid membrane is used to enrich and isolate analytes from a complex sample. The liquid membrane, which is immiscible with water and the sample matrix, is immobilized in the pores of a porous hollow fiber. Such a liquid membrane is referred to as a supported liquid membrane (S LM). Immobilization of the SLM is achieved by simply dipping the hollow fiber in an organic solvent allowing the pores to be filled. Figure 9.11 shows a schematic representation of LPME. [Pg.185]