Polyacrylate-coated fibers, solid-phase

LLE, liquid-liquid extraction MAE, microwave-assisted extraction SEE, solid-phase extraction SPME, solid-phase microextraction LPME, liquid-phase microextraction SOME, single-drop microextraction D-LLLME, dynamic liquid-liquid-liquid microextraction SEE, supercritical fluid extraction MIP, molecularly imprinted polymers sorbent SPMD, device for semipermeable membrane extraction PDMS, polydimethylsiloxane coated fiber PA, polyacrylate coated fiber CW-DMS, Carbowax-divinylbenzene fiber PDMS-DVB, polydimethylsiloxane divinylbenzene fiber CAR-PDMS, Carboxen-polydimethylsiloxane coated fiber DVB-CAR-PDMS, divinylbenzene Carboxen-polydimethylsiloxane coated fiber CW-TPR, Carbowax-template resin HS-SPME, headspace solid-phase microextraction MA-HS-SPME, microwave-assisted headspace-solid-phase microextraction HEM, porous hollow fiber membrane PEl-PPP, polydydroxylated polyparaphenylene. 

J.-L. Liao, C-M. Zeng, S. Hjeiten and J. Pawliszyn, Solid phase micro exti action of biopolymers, exemplified with adsorption of basic proteins onto a fiber coated with polyacrylic acid , ]. Microcolumn Sep. 8 1-4. (1996)... 

In the 1990s, Pawliszyn [3] developed a rapid, simple, and solvent-free extraction technique termed solid-phase microextraction. In this technique, a fused-silica fiber is coated with a polymer that allows for fast mass transfer—both in the adsorption and desorption of analytes. SPME coupled with GC/MS has been used to detect explosive residues in seawater and sediments from Hawaii [33]. Various fibers coated with carbowax/divinylbenzene, polydimethylsiloxane/divinylbenzene, and polyacrylate are used. The SPME devices are simply immersed into the water samples. The sediment samples are first sonicated with acetonitrile, evaporated, and reconstituted in water, and then sampled by SPME. The device is then inserted into the injection port of the GC/MS system and the analytes thermally desorbed from the fiber. Various... 

GC combined with mass spectroscopic (MS) detection provides very accurate identification and quantification of FFAs. Pinho et al. (2003) monitored changes in the FFA content during the ripening of ewe cheese. Sampling was done by headspace solid-phase microextraction (SPME). An excellent correlation was observed between the initial concentration of the sample and the amount absorbed on the SPME fiber. SPME sampling was done at 65 °C with a fiber coated with 85-p.m polyacrylate film. After equilibration at 65 °C for 40 min, the fiber was exposed to the sample headspace for 20 min and inserted into the GC port. Despite its accuracy, the GC-MS method is not widely used, presumably because of its cost and complexity. 

Figure 11.15 Cation-exchange micro-LC analysis of a mixture of model proteins (a) the original sample consisting of myoglobin (M), cytochrome C (C) and lysozyme (L) (b) and (c) proteins adsorbed on to and then released from the polyacrylic acid coated fibre with extraction times of 5 and 240 s, respectively. Reprinted from Journal of Microcolumn Separations, 8, J.-L. Liao et al., Solid phase micro extraction of biopolymers, exemplified with adsorption of basic proteins onto a fiber coated with polyacryfic acid, pp. 1-4, 1996, with permission from John Wiley Sons, New York.

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 the early 90s, a new technique called solid-phase-micro extraction (SPME), was developed (Arthur and Pawliszyn, 1990). The key-part component of the SPME device is a fused silica fiber coated with an adsorbent material such as polydimethylsiloxane (PDMS), polyacrylate (PA) and carbowax (CW), or mixed phases such as polydimethylsiloxane-divinylbenzene (PDMS-DVB), carboxen-polydimethylsiloxane (CAR-PDMS) and carboxen-polydimethyl-siloxane-divinylbenzene (CAR-PDMS-DVB). The sampling can be made either in the headspace (Vas et al., 1998) or in the liquid phase (De la Calle et al., 1996) of the samples. The headspace sampling in wine analyses is mainly useful for quantifying trace compounds with a particular affinity to the fiber phase, not easily measurable with other techniques. Exhaustive overviews on materials used for the extraction-concentration of aroma compounds were published by Ferreira et al. (1996), Eberler (2001), Cabredo-Pinillos et al. (2004) and Nongonierma et al. (2006). Analysis of the volatile compounds is usually performed by gas chromatography (GC) coupled with either a flame ionization (FID) or mass spectrometry (MS) detector. 

As a result of the increase in the number of laboratories carrying out environmental analysis and the corresponding increase in the volumes that are used primarily for extraction and have to be disposed of, there has been increasing use of solid-phase extraction (SPE) methods including solid-phase microextraction (SPME) procedures using fiber-coated poly(dimethylsilox-ane), methyl silicone, or polyacrylate. These procedures are discussed in Sections 2.2.4 and 2.2.7. 

Solid-phase microextraction (SPME) in open-tobular fused-silica capillary columns or in fused-silica or Carbowax-templated poly(divinylbenzene) resin fibers coated or filled with a stationary phase (polydimethylsiloxane or polyacrylate) 2 has recently been used to extract analytes from liquid or gaseous samples. This procedure is more restricted to the extraction of volatile compounds, which are... 

Similar to the properties of divinylbenzene porous polymer phases higher polarity than Carbowax, and when combined with Carbowax results in a more polar phase like polyacrylate, it is a solid particle that must be carried in a liquid to coat on a fiber. 

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