Solid-phase microextraction divinylbenzene

GCB = graphitized carbon black SPME = solid-phase microextraction PDMS = polydimethylsiloxane PS = polystyrene DVB = divinylbenzene SDB = styrene-divinylbenzene. 

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... 

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... 

Concentrator materials of choice are often polymers. Polydimethylsiloxane (PDMS), or a polydimethylsiloxane/divinylbenzene copolymer (PDMS/DVB) are favored choices for explosive molecules. PDMS are often used in the form of solid-phase microextraction (SPME) fibers. PDMS/DVB is often used in the form of microspheres with diameters in the 50- to 75-pm range. Detailed considerations for use of SPME fibers is given on a website maintained by the University of Western England [19], It references a more complete treatise [20], Other geometries, such as stacked spheres, have also been used successfully [21],... 

Figure 15.4 Binding of bombykol to BmPBP at pH 7 as demonstrated by the cold-binding assay. After removal of the unbound ligand, bound bombykol was extracted from the ligated protein with a solid phase microextraction syringe (SPME, 65 pm polydimethylsiloxane divinylbenzene coating). Under the same conditions, but at low pH (5), the amount of ligand extracted is not significantly different from the amount extracted from a buffer solution (control).

Recently, rotundone was identified as a pepper aroma impact compound in Shiraz grapes (Siebert et al.,2008). Identification was achieved by performing GC-MS analysis of grape juice after purification by solid-phase extraction (SPE) using a styrene-divinylbenzene 500-mg cartridge and elution with n-pentane/ethyl acetate 9 1, followed by solid-phase microextraction (SPME) using a 65-pm polydimethylsilox-ane-divinylbenzene (PDMS/DVB) fiber immersed in the sample for 60 min at 35 °C. J5-Rotundone was used as an internal standard. The structure of the compound is reported in Fig. 4.5. 

Solid phase microextraction (SPME) was used to determine the presence of volatiles in cranberry seed extract. The optimized SF extract was diluted with 5mL of a mixture of dichloromethane and methanol (1 1). A carbowax/divinylbenzene (CW/DVB) fiber was exposed for 60 min to the headspace of the diluted cranberry seed extract. The assembly was kept at 30 C with stirring. The fiber was then desorbed for 5 min in the injection port of an HP 6890 Series GC interfrced with a HP 5973 Series MSD. The injector temperature was maintained at 220 C. The helium flow was kept at 2mL/min. The oven temperature was initially maintained at 40°C for 3 min and then ramped at 4°C/min to 100 C and finally heated to 220°C at 15°C/min. 

LLE liquid-liquid extraction SPE solid-phase extraction SPM solid-phase microextraction MAE microwave-assisted extraction SEE supercritical fluid extraction FMASE focused microwave-assisted Soxhlet extraction PSDB polystyrene-divinylbenzene NVPDB A-vinylpyrrolidane-divinylbenzene SPE solid-phase extraction LLE liquid-liquid extraction GPC gel permeation chromatography OPA f -phthalaldehyde reagent TAD thermally assisted desorption FI flow injection... 

Several SP materials have been used for the extraction of FRs from aqueous samples, plasma and milk (Table 31.7). Similar materials have been used for all FRs. Typical SP materials include Ci8 and Cg bonded to porous silica, highly cross-linked poly(styrene divinylbenzene) (PS-DVB), and graphitized carbon black (GCB). It is also possible to use XAD-2 resin for extraction of various FRs, pesticides, and plastic additives from large volumes of water (100 1). The analytes can then be either eluted from the resin by acetone hexane mixture, or Soxhlet extracted with acetone and hexane. For a specific determination of diphenyl phosphate in water and urine, molecularly imprinted polymers have been used in the solid phase extraction. The imprinted polymer was prepared using 2-vinylpyridine as the functional monomer, ethylene glycol dimethacrylate as the cross linker, and a structural analog of the analyte as the template molecule. Elution was done with methanol triethylamine as solvent. Also solid phase microextraction (SPME) has been applied in the analysis of PBDEs in water samples. The extraction has been done from a headspace of a heated water sample (100°C) using polydimethylsiloxane (PDMS) or polyacryl (PA) as the fiber material. ... 

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. 

PDMS/DVB, polydimethylsiloxane/divinylbenzene coated fiber SPME, solid-phase microextraction. 

A solventless technique of solid-phase microextraction (SPME) has been also employed for HPLC determination of MC in a natural Microcystins sp. bloom in a freshwater, where three dominant MC variants MC-LR, -YR, and -RR were quantified. For this purpose a measuring system with commercial SPME-HPLC interface was employed. Microcystins were sorbed from acidified solutions using SPME fibers with carbowax/templated resin and polydi-methylsiloxane/divinylbenzene coating and desorbed at dynamic mode with HPLC eluent, which was used in isocratic elution mode and consisted of water and methanol with 0.05% TFA. For each toxin partition equilibrium was achieved within 60 min and example response obtained in SPME-HPLC system is shown in Fig. 6. The detection limits for all examined MC for 5 ml samples were reported at about 7 ppb. 

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. 

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... 

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. 

C Sala, M Mestres, MP Marti, O Busto, J Guasch. Headspace solid phase microextraction method for determining 3-alkyl-2-methoxypyrazines in musts by means of polydimethylsiloxane-divinylbenzene fibers. J Chromatogr A... 

Fibers coated with silicone/divinylbenzene copolymer have been demonstrated for solid phase microextraction of AE from water (64). Fibers coated with PEG-based polymers have similarly been demonstrated for solid phase microextraction of OPE (65). 

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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