Thermal Immobilization of Poly(Butylacrylate) on Glass-Ceramic Rod for Preparation of Solid Phase Microextraction Fibers (original) (raw)
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H ollow-fibre liquid-phase microextraction of phthalate esters from water
A simple and efficient liquid-phase microextraction (LPME) technique using a hollow-fibre membrane, in conjunction with gas chromatography–mass spectrometry has been developed for the extraction and analysis of six phthalate esters in water samples. Parameters such as extraction solvent, agitation of the sample, salt addition and extraction time were controlled and optimised. The developed protocol was found to yield a linear calibration curve in the concentration range 21 21 from 0.02 to 10 mg l for most target analytes and the limits of detection were in the low mg l level, ranging between 21 0.005 and 0.1 mg l. The repeatability of the method varied between 4% and 11%. Under the present experimental conditions, the performance of the method was found comparable to that of solid-phase microextraction (SPME). The advantage of the proposed method over SPME was that it eliminated carry-over of analytes between runs. The applicability of the developed hollow-fibre LPME method and SPME was demonstrated for real water samples. The ability of both microextraction methods to concentrate many organic analytes was demonstrated as both methods allowed the confirmation of the presence of an extra contaminant (ethyl p-ethoxybenzoate) in bottled mineral water samples.
Journal of Applied Polymer Science, 2015
The electrospinning technique was applied to coat fused silica fibers with regenerated silk fibroin (RSF) nanofibers, aiming to build a device applicable for solid phase microextraction analysis. The device was characterized by attenuated total reflectance infrared spectroscopy, thermal analyses (differential scanning calorimetry and thermogravimetric analysis), and scanning electron microscopy, and employed to extract/desorb isopropyl alcohol (IPA) from the headspace of an IPA aqueous solution. The electrospun coating proved to be thermally stable up to 250 C, even after 4 h of exposure to this temperature. A 2 2 factorial experimental design was used to evaluate the flow rate of the polymer solution and the distance between capillary tip and collector on the mean RSF fiber diameter. A low flow rate (0.20 mL h 21) and large capillary tip-to-collector distance (12 cm) yielded fibers with mean diameter of (304 6 46 nm). The nanofibers were heated to 250 C, simulating the conditions in the injector of a gas chromatograph (GC). In these conditions, the RSF nanofibers were found not to melt even after 4 h of exposure to heat, although slight structural damage was detected. Preliminary assays using the as-constructed device built under optimized electrospinning conditions (0.20 mL h 21 and 12 cm) were performed in a GC by contact with the headspace of a 50 ppm IPA solution to determine the extraction and desorption times. The results indicated that the extraction process stabilized after 20 min of contact with the headspace of the IPA solution. The desorption process was complete after 10 min at 140 C.
Inorganic/organic mesoporous silica as a novel fiber coating of solid-phase microextraction
Talanta, 2004
Mesoporous materials were employed as fast, sensitive and efficient fiber coatings of solid-phase microextraction (SPME) for the first time. Three micrometer as-synthesized C(16)-MCM-41 particles were immobilized onto stainless steel wire with 100mum coating thickness. In combination with high performance liquid chromatography (HPLC), extraction efficiency and selectivity of C(16)-MCM-41 were investigated using aromatic hydrocarbons. Effect of extraction and desorption time, extraction temperature, stirring rate and ionic strength on extraction efficiency were examined. Aanalytical merits of SPME with C(16)-MCM-41 coating were evaluated. The chromatographic peak area is proportional to the concentration of anthracene in the range 0.5-150mugl(-1). The limit of detection was 0.05mugl(-1) (S/N=3) and the relative standard deviation (R.S.D.) was 0.033%.
Journal of Separation Science, 2012
In the present work, the effect of substrate porosity for preparation of solid-phase microextraction (SPME) fibers was investigated. The fibers were prepared by electrodeposition of sol-gel coatings using negative potentials on porous Cu wire and compared with previous reported technique for preparation of SPME fibers using positive potentials on smooth gold wire. Porous substrate was prepared by electrodeposition of a thin layer of Cu on a Cu wire. The extraction capability of prepared fibers was evaluated through extraction of some aromatic hydrocarbons from the headspace of aqueous samples. The effect of substrate porosity and some operating parameters on extraction efficiency was optimized. The results showed that extraction efficiency of SPME fibers highly depends on porosity of the substrate. The LOD ranged from 0.005 to 0.010 ng/mL and repeatability at the 1 ng/mL was below 12%. Electrodeposited films were characterized for their surface morphology and thermal stability using SEM and thermogravimetric analysis, respectively. SEM analysis revealed formation of porous substrate and subsequently porous coating on the wire surface and thermogravimetric analysis showed high thermal stability of the prepared fiber.
Journal of chromatography. A, 2015
In the present study, 12-tungstophosphoric (PW) acid as heteropoly acid, supported on silica-coated γ-Fe2O3 nanoparticles (NPs), was used as a new fiber coating for solid-phase microextraction (SPME). The γ-Fe2O3@SiO2-PW nanocomposite with high surface area was synthesized and characterized by SEM and FT-IR. The prepared nanocomposite was immobilized on a stainless steel wire for fabrication of the SPME fiber. The fiber was evaluated for the extraction of some phenolic compounds (PCs) from water sample in combination with gas chromatography-mass spectrometry (GC-MS). A one-at-a-time optimization strategy was applied for optimizing the important extraction parameters such as extraction temperature, extraction time, ionic strength, stirring rate, pH, and desorption temperature and time. In optimum conditions, the repeatability for one fiber (n=3), expressed as relative standard deviation (R.S.D. %), was between 4.8% and 9.6% for the test compounds. The detection limits for the studied...
Journal of the Chinese Chemical Society, 2012
LUS-1 typed nanoporous silica particles were synthesized and silylated with hexamethyldisilazane and investigated as a highly porous fiber coating for solid-phase microextraction (SPME). The pore size distribution of the prepared Sil-LUS-1 was still typical of MCM-41 and centered at 3 nm with a specific surface area of 720 m 2 g -1 . The SPME fiber was prepared by liming the material on a copper wire. The extraction efficiency of the new fiber was compared with a commercial PDMS fiber for headspace extraction and GC-MS analysis of phenol, 4-nitrophenol, 2,4-dichlorophenol and 4-chlorophenol in water samples. Due to the high porosity of the prepared fiber it showed a higher sensitivity and better selectivity for the extraction of the target compounds. For optimization of different factors affecting the extraction efficiency, a simplex optimization method was used. The relative standard deviation for the measurements by one fiber was better than 7% for five replicates and the fiber-to-fiber reproducibility was about 10% for five fabricated fibers. Detection limits in the range of 0.002 to 0.026 mg mL -1 were obtained for the phenolic compounds. The fiber was successfully applied for the determination of phenolic compounds in natural water samples.
Journal of Chromatography A, 2008
In this study zirconium oxide electrolytically deposited onto a NiTi alloy (NiTi-ZrO 2) was employed as a new substrate for sol-gel reactions for the fabrication of an efficient and unbreakable solid-phase microextraction fiber. The NiTi-ZrO 2 surface was activated and used as a substrate for coating with poly(ethylene glycol) sol solution. Fibers produced with and without a ZrO 2 layer were compared and, through scanning electron micrographs, an excellent attachment of the polymer in the case of the NiTi-ZrO 2 substrate was demonstrated. The proposed fiber showed excellent thermal stability up to the maximum temperature evaluated of 320 • C, suggesting a strong interaction between the substrate surface and the polymeric coating, probably due to chemical bonding. The applicability of the proposed fiber was evaluated through extraction of halophenols and phthalate esters from the headspace and directly from aqueous sample, respectively. Some parameters affecting the extraction efficiency were optimized by full-factorial and Doehlert experimental designs, and the analytical features were estimated. Detection limits in the range of 1.2-9.8 ng L −1 for halophenols and 0.3-0.7 g L −1 for phthalate esters were obtained. Repeatability for one fiber (n = 6) was in the range of 4.6-10.6% and fiber-to-fiber reproducibility (n = 5) was lower than 12% for all compounds. The results suggest that the proposed fiber can be successfully applied for the determination of these compounds in water and also can be extended to other analytes and matrices.
Electrospun Fibers for Solid-Phase Microextraction
Analytical Chemistry, 2010
A method of producing solid phase microextraction (SPME) fibers based on electrospinning polymers into nanofibrous mats is demonstrated. Using this method the polymer mat is attached to a stainless steel wire without the need of a binder. While applicable to any polymer that can be electrospun, SU-8 2100, a polymeric negative photoresist, is used for this initial study. SPME devices comprised of carbon nanofibers are also illustrated by pyrolizing SU-8 to produce amorphous carbon. Nonpolar compounds, benzene, toluene, ethylbenzene, and o-xylene (BTEX) and polar compounds, phenol, 4-chlorophenol and 4nitrophenol are extracted under headspace SPME conditions. Extraction efficiencies are compared to commercial polydimethylsiloxane (PDMS), polydimethylsiloxane/divinylbenzene (PDMS/DVB) and polyacrylate (PA) fibers. For both the nonpolar and polar compounds, the carbon nanofiber based phases demonstrated enhanced or comparable (o-xylene only) extraction efficiencies.