Solid-phase microextraction Carboxen

Solid-phase microextraction (SPME) consists of dipping a fiber into an aqueous sample to adsorb the analytes followed by thermal desorption into the carrier stream for GC, or, if the analytes are thermally labile, they can be desorbed into the mobile phase for LC. Examples of commercially available fibers include 100-qm PDMS, 65-qm Carbowax-divinylbenzene (CW-DVB), 75-qm Carboxen-polydimethylsiloxane (CX-PDMS), and 85-qm polyacrylate, the last being more suitable for the determination of triazines. The LCDs can be as low as 0.1 qgL Since the quantity of analyte adsorbed on the fiber is based on equilibrium rather than extraction, procedural recovery cannot be assessed on the basis of percentage extraction. The robustness and sensitivity of the technique were demonstrated in an inter-laboratory validation study for several parent triazines and DEA and DIA. A 65-qm CW-DVB fiber was employed for analyte adsorption followed by desorption into the injection port (split/splitless) of a gas chromatograph. The sample was adjusted to neutral pH, and sodium chloride was added to obtain a concentration of 0.3 g During continuous... 

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. 

Popp, P. and Paschke, A., Solid phase microextraction of volatile organic compounds using carboxen-polydimetbylsiloxane fibers, Chromatographia, 46(7-8), 419-424, 1997. 

DBTHS, disodium 5,13-his(dodecyloxymethyl-4,7.11,14-tetraoxa-l,17-heptadecanedisulfonate ITP, isotachophoresis m-HEC, methyl-hydroxyethylcellulose PVP, polyvinylpirrolidone PSDVB, polystyrene-divinylbenzene copolymer SB-P-CD, sulfobutylether-p-cyclodextrin CAR-PDMS, carboxen-polyfdimefhylsiloxane) ESI-IT-MS, electrospray ionization ion trap-mass spectrometry CHES, 2-(V-cyclohexylamino)-ethanesulphonic acid CAPS, 3-(cyclohexylamino)-l-propanesttlfonic acid PHWE, pressurized hot water extraction ICP-MS, inductively coupled plasma-mass spectrometry SPME, solid-phase microextraction SPE, solid-phase extraction. 

The quest for new suitable materials represents a similar trend in the development of the solid-phase microextraction (SPME) techniques. Polypyrrole and poly N-phenylpyrrole films exhibit better selectivity toward polar, aromatic, and basic pesticides, due to their inherent multifunctional properties. Their high surface areas (also revealed by scanning electron microscopy) are responsible for the high extraction efficiencies shown by these materials. Mixtures of divinyl-benzene, carboxen, and polydimethylsiloxane-based... 

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. 

The solid-phase microextraction device (SPME) was purchased from Supelco Co. (Bellefonte, PA). The following types of SPME fiber were used polydimethylsiloxane (PDMS) with lOO-pm thickness, PDMS/ divinylbenzene (DVB) with 65-pm thickness, and Carboxen (Supelco Co., Bellefonte, PA, U.S.A.)/PDMS (CAR/PDMS) with 75-pm thickness. 

Figure 2 T5 pical total ion chromatograms of the static headspace volatiles of ground roasted Ethiopia coffee beans (roast degree L23) obtained by three different solid-phase microextraction fibers. PDMS, polydimethyl siloxane DVB, divinylben-zene CAR, carboxen.

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