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1.
Optimization of the SPME device design for field applications 总被引:2,自引:0,他引:2
Solid Phase Microextraction (SPME) is a powerful tool for field investigations. With the help of a portable gas chromatograph
it can be used for fast analysis directly on-site, or it can be utilized for field sampling and then transported to the laboratory
for instrumental analysis. In the latter case, it is important for the reliability of the results that losses of volatiles
and contamination of the fiber during storage and transport are minimized. A number of dedicated devices, designed and built
for SPME field sampling and storage, have been developed and tested. Sealing capacity of the prototypes was investigated by
storing compounds ranging in volatility from methylene chloride to 1,3-dichlorobenzene on selected SPME fibers (100 μm PDMS,
65 μm PDMS/DVB and 75 μm Carboxen/PDMS) at different temperatures. Significant differences were noticed in storage capacity
from coating to coating. A comparison between the field samplers optimized in this study and the field sampler commercially
available from Supelco revealed advantages and limitations of each of the designs. A gas-tight valve syringe (50 μL SampleLock
by Hamilton), modified in order to accommodate the SPME fiber, had the best storage capacity for very volatile compounds.
With this device, over 80% of the initial amount of methylene chloride was retained by the 100 μm PDMS fiber after 24 h of
refrigerated storage, which is a very good result considering that the PDMS coating is characterized by very low storage capacity
for volatiles. Field sampling investigations with the SPME prototypes confirmed the usefulness of these devices for field
analysis.
Received: 9 November 1998 / Accepted: 15 January 1999 相似文献
2.
Solid phase microextraction of volatile organic compounds using carboxen-polydimethylsiloxane fibers
Summary A new 80 μm Carboxen-polydimethylsiloxane (PDMS) fiber for solid phase microextraction (SPME) was tested for the enrichment
of volatile organic compounds from water and air. Detection limits between 13 ng L−1 (CH2Cl2) and 0.1 ng L−1 (CHCl2Br and CHClBr2) for the combination: Carboxen-PDMS fiber and GC-ECD and between 35 ng L−1 and 45 ng L−1 (BTEX compounds) for the combination: Carboxen-PDMS and GC-FID using the headspace procedure were determined. Comparisons
with the 100 μm PDMS fiber and further coatings show the advantages of the Carboxen-PDMS fiber with respect to extraction
efficiency. Disadvantages of the new fiber compared with the 100 μm PDMS fiber are poorer repeatability and prolongation of
equilibrium time. Distribution coefficients of the BTEX compounds between aqueous solution and SPME fiber coating were calculated
and compared with the results of other researchers and with octanol-water partition coefficients. 相似文献
3.
Joeri Vercammen Pat Sandra Erik Baltussen Tom Sandra Frank David 《Journal of separation science》2000,23(9):547-553
Static and dynamic headspace sampling have been applied for the enrichment of volatiles emitted by living plants. For solid phase microextraction (SPME) the sorptive fibers polydimethylsiloxane (PDMS) and polyacrylate (PA) have been compared and, in accordance with the like‐like principle, polar compounds exhibit more affinity for the PA fiber while apolar solutes favor the PDMS fiber. For dynamic sampling, tubes packed with PDMS particles show greater inertness than Tenax; some Tenax decomposition products, e.g. benzaldehyde and acetophenone, interfere with the analyses. With PDMS particles operated in the breakthrough mode, the obtained profiles are similar to those obtained by SPME on the PA fiber. Recoveries relative to a packed PDMS bed are 85% for Tenax, 2.4% for SPME‐PDMS, and 6.2% for SPME‐PA. 相似文献
4.
A new cloud vapor zone (CVZ)-based headspace solid-phase microextraction (HS-SPME) technique has been demonstrated with the
capability of heating the sample matrix and simultaneously cooling the sampling zone. A bi-temperature-controlled (BTC) system,
allowing 10 mL of test sample heating and headspace external-cooling, was employed for the CVZ formation around the SPME-fiber
sampling area. In the CVZ procedure, the heated headspace vapor undergoes a sudden cooling near the SPME to form a dense cloud
of analyte–water vapor, which is helpful for adsorption or absorption of the analyte. The device was evaluated for the quantitative
analysis of aqueous chlorothalonil. Parameters influencing sampling efficiency, e.g., SPME fiber coating, SPME sampling temperature
and time, solution modifier, addition of salt, sample pH, and temperature, were investigated and optimized thoroughly. The
proposed BTC-HS-SPME method afforded a best extraction efficiency of above 94% accuracy (less than 4.1% RSD, n = 7) by using the PDMS fiber to collect chlorothalonil in the headspace at 5 °C under the optimized condition, i.e., heating
sample solution (added as 10% ethylene glycol and 30% NaCl, at pH 7.0) at 130 °C for 15 min. The detection was linear from
0.01 to 80 μg L−1 with a regression coefficient of 0.9998 and had a detection limit of 3.0 ng L−1 based on S/N = 3. Practical application was demonstrated by analyzing chlorothalonil in farm water samples with promising
results and recoveries. The approach provided a very simple, fast, sensitive, and solvent-free procedure to collect analytes
from aqueous solution. The approach can provide a new platform for other sensitive HS-SPME assays. 相似文献
5.
Summary To assess individual exposure to monoaromatic hydrocarbons (benzene, toluene, ethylbenzene and xylenes-BTEX) in biological
fluids, a GC-MS method was developed. Headspace sampling of BTEX was by solidphase microextraction (SPME) with a 75 μm Carboxenpolydimethylsiloxane
(PDMS) fiber. Linearity was established for concentrations up to 50 μg L−1. Detection limits, calculated both in human blood and urine, ranged 5–10 ng L−1. Repeatability was in the range 6.5–9.2% for all compounds. The method was applied to the evaluation of the internal dose
of BTEX in a group of cyclists running for 2 h within city routes. Benzene and toluene in blood, and toluene and xylenes in
urine significantly increased after exercise as compared to prerun values, such changes being consistent with airborne concentrations.
The combination of SPME with GC-MS seems to represent an appropriate analytical approach to detect changes in the concentration
of monoaromatic hydrocarbons in biological media resulting from exposure to environmental pollution. 相似文献
6.
Johanna Tollbäck Sindra Isetun Anders Colmsjö Ulrika Nilsson 《Analytical and bioanalytical chemistry》2010,396(2):839-844
Methodology for time-weighted average (TWA) air measurements of semivolatile organophosphate triesters, widely used flame-retardants
and plasticizers, and common indoor pollutants is presented. Dynamic non-equilibrium solid-phase microextraction (SPME) for
air sampling, in combination with GC/PICI and ion trap tandem MS, yields a fast, almost solvent-free method with low detection
limits. Methanol was used as reagent gas for PICI, yielding stable protonated molecules and few fragments. A field sampler,
in which a pumped airflow over three polydimethylsiloxane (PDMS) 100-μm fibers in series was applied, was constructed, evaluated,
and used for the measurements. The method LODs were in the range 2–26 ng m−3 for a sampling period of 2 h. The uptake on the SPME fibers was shown to be about five times faster for triphenyl phosphate
compared to the other investigated organophosphate esters, most likely due to more lipophilic properties of the aromatic compound.
The boundary layer for triphenyl phosphate when using a 100-μm PDMS sorbent was determined to 0.08 mm at a linear air velocity
of 34 cm s−1. Five different organophosphate triesters were detected in air from a laboratory and a lecture hall, at concentrations ranging
from 7 ng m−3 up to 2.8 μg m−3. 相似文献
7.
López-Darias J Anderson JL Pino V Afonso AM 《Analytical and bioanalytical chemistry》2011,401(9):2965-2976
Two solid-phase microextraction (SPME) sorbent coatings based on polymeric ionic liquids (PILs) have been utilized for the
analysis of complex coffee aroma samples. The PIL-based SPME coatings examined, namely, poly(1-(4-vinylbenzyl)-3-hexadecylimidazolium
bis[(trifluoromethyl)sulfonyl]imide) [poly(VBHDIm+ NTf2−)], with ∼14-μm thickness, and poly(1-vinyl-3-hexylimidazolium chloride) [poly(ViHIm+ Cl−)], with ∼8-μm thickness, were employed for the headspace determination of up to 49 analytes from four different coffee beans:
two French roast coffees of different brands, Sumatra coffee, and decaffeinated Sumatra coffee. The analysis was conducted
using gas chromatography coupled to mass spectrometry. For comparative purposes, the commercial polyacrylate (PA, 85-μm film
thickness) SPME coating was utilized under the same extraction conditions. The three SPME coatings tested behaved quite differently
as a function of the families of compounds extracted. Thus, the poly(VBHDIm+ NTf2−) coating was extremely selective for aldehydes while also exhibiting good extraction efficiencies for acids. The poly-(ViHIm+ Cl−) coating exhibited superior performance for aromatic alcohols, and the PA coating worked better for heterocyclic aromatics.
Both PIL-based SPME sorbent coatings demonstrated exceptional selectivity and extraction efficiency when dealing with complex
coffee aromas in spite of their small film thicknesses. 相似文献
8.
Solid phase micro extraction (SPME) was investigated for the determination of volatile chemicals in the foliage of Fraser fir (Abies fraseri). Advantages of SPME include its speed, sensitivity, and ability to determine volatiles without chemical solvents. In this study, qualitative comparisons were performed of the volatiles emitted from living foliage (in situ), damaged living foliage (in situ damaged), and severed foliage (ex situ). These studies suggest that β-phellandrene and γ-terpinene may be emitted as a response to foliar injury. Comparisons were made of the volatiles collected by SPME with ex situ sampling to previous studies in our laboratory using methylene chloride extraction. Similar results were obtained by the two extraction methods. 相似文献
9.
Zhipei Qin Leslie Bragg Gangfeng Ouyang Vadoud H. Niri Janusz Pawliszyn 《Journal of chromatography. A》2009,1216(42):6979-6985
An electric drill coupled with a solid-phase microextraction (SPME) polydimethylsiloxane (PDMS) fiber or a PDMS thin film was used for rapid sampling of polycyclic aromatic hydrocarbons (PAHs) in aqueous samples. Laboratory experiments demonstrated that the sampling rates of SPME fiber and thin film can be predicted theoretically. Compared with the SPME fiber, the PDMS thin film active sampler exhibited a higher sampling rate and much better sensitivity due to its higher surface-to-volume ratio and its larger extraction phase volume. The amount of the analytes extracted by the thin film was around 100 times higher than those obtained by fiber, for both 5 min rapid sampling and equilibrium extraction. A new thin film active sampler was then developed for rapid on-site water sampling. The sampling kit included a portable electric drill, a copper mesh pocket, a piece of thin film, and a liner. Laboratory experiments indicated that the sampling remained in the linear uptake phase with this sampler to 8 min for the PAHs. Field test illustrated that this novel sampler was excellent for rapid on-site water sampling due to its short sampling period, high sampling efficiency and durability The thin film sampling kit facilitates on-site sampling, sample preparation, storage and transport. This new sampler is more user-friendly and easier to commercialize than previous samplers. 相似文献
10.
Isetun S Nilsson U Colmsjö A Johansson R 《Analytical and bioanalytical chemistry》2004,378(7):1847-1853
Solid phase micro-extraction (SPME) was used to collect air samples of semi-volatile organophosphate triesters, a group of compounds that are commonly used as flame retardants/plasticisers and have therefore become ubiquitous indoor air pollutants. SPME is a simple sampling technique with several major advantages, including time-efficiency and low solvent consumption. Analyte losses also tend to be relatively low. In quantitative SPME, measurements are normally taken after the analyte has reached partitioning equilibrium between the fibre and the sample matrix. However, equilibrium sampling of semi-volatile compounds in air with SPME often takes several hours. Clearly, time-weighted average (TWA) sampling using SPME under non-equilibrium conditions could be considerably faster. So, in this study, the possibility of sampling organophosphate triesters under non-equilibrium conditions was tested. The most important variables proved to be the fibre coating and the air velocity during sampling. The highest uptake rate was obtained with polydimethylsiloxane (PDMS, 100 m). The rate for this fibre was 150-fold higher than obtained with PDMS/DVB and Carbowax/DVB, both 65 m. Contrary to theoretical expectations, the uptake rate appeared to be constant for all tested air velocities over the fibre surface >7 cm/s. These findings suggest that the uptake rate for non-equilibrium SPME sampling is independent of the sampling flow above this flow rate, which would considerably enhance the robustness and flexibility of the method. Applying this method for TWA sampling, with sampling periods of 1 h, detection limits lower than 2 ng/m3 for individual organophosphate esters were obtained. 相似文献
11.
Giuliana Bianco Giuseppe Novario Rosalia Zianni Tommaso R. I. Cataldi 《Analytical and bioanalytical chemistry》2009,393(8):2019-2027
Headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography with high-resolution mass spectrometry (GC–HRMS)
was used to determine 2,4,6-trichloroanisole, 2,3,6-trichloroanisole, 2,3,4-trichloroanisole, 2,3,5,6-tetrachloroanisole,
pentachloroanisole, 2,4,6-tribromoanisole, 2-methylisoborneol, and 4-ethylguaiacol in wine samples. Two types of fiber coating
commonly employed for sampling trichloroanisoles in wine and cork stoppers, viz. a polar mixed 50/30 μm divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) and a nonpolar 100 μm polydimethylsiloxane
(PDMS), both 1 cm in length, were compared. This study demonstrates that the most employed polar mixed fiber should not be
used with ethanol–water solutions, viz. wine samples, as its coating is not chemically and mechanically robust for sample extractions, as confirmed by environmental
scanning electron microscopy. Much more effective and reliable results were obtained with the PDMS fiber, which remained functional
for more than 80 analyses of red and white wine samples with satisfactory extraction efficiencies. Detection limits of investigated
compounds, under optimized experimental conditions, ranged from 0.2 to 0.4 ng/L at a signal-to-noise ratio of 3 and quantification
limits from 0.8 to 1.5 ng/L. The proposed method was successfully applied to commercially available Italian white and red
wines using 2,4,6-TCA-d5 as the internal standard.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Presented, in part, at the XXI Congresso Nazionale di Chimica Analitica, 21–25 September 2008, Arcavacata di Rende, CS (Italy). 相似文献
12.
Analysis of volatiles of malt whisky by solid-phase microextraction and stir bar sorptive extraction
Demyttenaere JC Martínez JI Verhé R Sandra P De Kimpe N 《Journal of chromatography. A》2003,985(1-2):221-232
Blended Scotch whisky was analysed by solid-phase microextraction (SPME) and stir bar sorptive extraction (SBSE) to study the composition of the volatiles. For SPME analysis, three different fibres were compared, poly(dimethylsiloxane) (PDMS) (100 microm). poly(acrylate) (PA) (85 microm) and divinylbenzene-Carboxen on poly(dimethylsiloxane) (DVB-CAR-(PDMS) (50/30 microm). It was found that the PDMS and DVB-CAR-PDMS fibres showed a higher enrichment capacity than PA as well as a better reproducibility. The influence of sampling time, temperature and salt addition on the enrichment of volatiles as well as the difference between liquid and headspace SPME were studied. An optimum SPME method was developed. Finally a more recent sample preparation technique, namely SBSE was evaluated to extract whisky volatiles. 相似文献
13.
ZnO nanorod array coating is a novel kind of solid-phase microextraction (SPME) fiber coating which shows good extraction capability due to the nanostructure. To prepare the composite coating is a good way to improve the extraction capability. In this paper, the ZnO nanorod array polydimethylsiloxane (PDMS) composite SPME fiber coating has been prepared and its extraction capability for volatile organic compounds (VOCs) has been studied by headspace sampling the typical volatile mixed standard solution of benzene, toluene, ethylbenzene and xylene (BTEX). Improved detection limit and good linear ranges have been achieved for this composite SPME fiber coating. Also, it is found that the composite SPME fiber coating shows good extraction selectivity to the VOCs with alkane radicals. 相似文献
14.
Jessica López-Darias Verónica Pino Jared L. Anderson Christa M. Graham Ana M. Afonso 《Journal of chromatography. A》2010,1217(8):1236-1243
The determination of a group of eighteen pollutants in waters, including polycyclic aromatic hydrocarbons and substituted phenols, is conducted in direct-immersion solid-phase microextraction (SPME) using the polymeric ionic liquid (PIL) poly(1-vinyl-3-hexadecylimidazolium) bis[(trifluoromethyl)sulfonyl]imide as a novel coating material. The performance of the PIL fiber coating in the developed IL-SPME-gas chromatography (GC)–mass spectrometry (MS) method is characterized by average relative recoveries of 92.5% for deionized waters and 90.8% for well waters, average precision values (as relative standard deviations, RSD%) of 11% for deionized waters and 12% for well waters, using a spiked level of 5 ng mL−1. The detection limits oscillate from 0.005 ng mL−1 for fluoranthene to 4.4 ng mL−1 for 4-chloro-3-methylphenol, when using an extraction time of 60 min with 20 mL of aqueous sample. The extraction capabilities of the PIL fiber have been compared with the commercial SPME coatings: polydimethylsyloxane (PDMS) 30 μm, PDMS 100 μm and polyacrylate (PA) 85 μm. The PIL fiber is superior to the PDMS 30 μm for all analytes studied. A qualitative study was also carried out to compare among the nature of the coating materials by normalizing the coating thickness. The PIL material was shown to be more efficient than the PDMS material for all analytes studied. The PIL coating was also adequate for nonpolar analytes whereas the PA material was more sensitive for polar compounds. 相似文献
15.
The Use of a Thin Glass-Ceramic Rod as a Surface for Sol-Gel Coating in the Preparation of SPME Fibers 总被引:4,自引:0,他引:4
A. Fernandes de Oliveira C. Berto da Silveira S. Denofre de Campos E. Antônio de Campos E. Carasek 《Chromatographia》2005,61(5-6):277-283
The efficiency of a glass-ceramic rod as a base for the preparation of SPME fibers using sol-gel technology was investigated. Glass-ceramic rod was coated with PDMS using sol-gel reaction, and its surface characteristic was determined for SEM. Optimum conditions for the preparation of the fiber are presented. The same procedure was used for coating the fused silica rod. The fibers thickness and absorption capacity were compared. The proposed fiber was used for the extraction of a mixture of BTEX, from aqueous samples. The results obtained proved the superiority of glass-ceramic as a new base for SPME fiber, resulting in a thickness of ~44 m against 6 m for fused silica base. The calibration graphs for BTEX were linear (r > 0.998) and the detection limits were below 0.8 g L–1. 相似文献
16.
固相微萃取-气相色谱/质谱分析栀子花的头香成分 总被引:30,自引:0,他引:30
分别用固相微萃取和动态顶空法分离栀子鲜花的头香成分,用GC/MS技术分析鉴定,并用GC/MS总离子流色谱峰的峰面积进行归一化定量。在固相微萃取方法中,共鉴定了54种化学成分,占总峰面积的99.98%。主要成分(质量分数)依次为金合欢烯(64.86%)、罗勒烯(29.33%)、芳樟醇(2.74%)、惕各酸顺式叶醇酯(1.34%)和苯甲酸甲酯(0.25%)等。经与动态顶空法的分析结果比较发现,固相微萃取法不仅操作简便,而且具有较高的采样灵敏度,获得的化学成分的信息量多于动态顶空法。 相似文献
17.
López Monzón A Vega Moreno D Torres Padrón ME Sosa Ferrera Z Santana Rodríguez JJ 《Analytical and bioanalytical chemistry》2007,387(6):1957-1963
Solid-phase microextraction (SPME) coupled with high-performance liquid chromatography (HPLC) with fluorescence detection
was optimized for extraction and determination of four benzimidazole fungicides (benomyl, carbendazim, thiabendazole, and
fuberidazole) in water. We studied extraction and desorption conditions, for example fiber type, extraction time, ionic strength,
extraction temperature, and desorption time to achieve the maximum efficiency in the extraction. Results indicate that SPME
using a Carboxen–polydimethylsiloxane 75 μm (CAR–PDMS) fiber is suitable for extraction of these types of compound. Final
analysis of benzimidazole fungicides was performed by HPLC with fluorescence detection. Recoveries ranged from 80.6 to 119.6
with RSDs below 9% and limits of detection between 0.03 and 1.30 ng mL−1 for the different analytes. The optimized procedure was applied successfully to the determination of benzimidazole fungicides
mixtures in environmental water samples (sea, sewage, and ground water). 相似文献
18.
Volatile organic compounds (VOCs) and odors in cattle rumen gas have been characterized by in-vivo headspace sampling by solid-phase
microextraction (SPME) and analysis by gas chromatography–mass spectrometry–olfactometry (GC–MS–O). A novel device enabling
headspace SPME (HS-SPME) sampling through a cannula was designed, refined, and used to collect rumen gas samples from steers.
A Carboxen–polydimethylsiloxane (PDMS) fiber (85 μm) was used for SPME sampling. Fifty VOCs from ten chemical groups were
identified in the rumen headspace. The VOCs identified had a wide range of molecular weight (MW) (34 to 184), boiling point
(−63.3 to 292 °C), vapor pressure (1.05 × 10−5 to 1.17 × 102 Pa), and water solubility (0.66 to 1 × 106 mg L−1). Twenty-two of the compounds have a published odor detection thresholds (ODT) of less than 1 ppm. More than half of the
compounds identified are reactive and have an estimated atmospheric lifetime of <24 h. The amounts of VFAs, sulfide compounds,
phenolic compounds, and skatole, and the odor intensity of VFAs and sulfide compounds in the rumen gas were all higher after
feeding than before feeding. These results indicate that rumen gases can be an important potential source of aerial emissions
of reactive VOCs and odor. In-vivo sampling by SPME then GC–MS–O analysis can be a useful tool for qualitative characterization
of rumen gases, digestion, and its relationship to odor and VOC formation.
Figure Modified cannula for rumen gas sampling with SPME 相似文献
19.
《Journal of separation science》2003,26(17):1563-1568
Solid‐phase microextraction (SPME) has been directly coupled to an ion‐trap mass spectrometer (MS) for the determination of the model compound lidocaine in urine, hereby applying MS/MS [fragmentation of [M + H]+ (m/z 235) to a fragment with m/z 86]. The throughput of samples has been increased using non‐equilibrium SPME with polydimethylsiloxane (PDMS) fibers. The effect of temperature on the sorption and the desorption was studied. Elevated temperatures during sorption (65°C) and desorption (55°C) had a considerable influence on the speed of the extraction. The desorption was carried out with a home‐made desorption chamber allowing thermostating. Only 1 min sorption and 1 min desorption were performed, after which MS detection took place, resulting in a total analysis time of 3 min. Detection limits below 1 ng/mL could be obtained despite yields of only 2.1 and 1.5% for a 100‐ and a 30‐μm PDMS‐coated fiber, respectively. Furthermore, the determination of lidocaine in urine had acceptable reproducibilities, i.e., relative standard deviations (RSDs) below 10%. A limit of quantitation (RSD < 15%) of about 1 ng/mL was obtained. No extra wash step of the extraction fiber was required after desorption if a 30‐μm coating was used, whereas not all the analyte was desorbed from the 100‐μm coating in a single desorption. Therefore, the SPME‐MS/MS system with a 30‐μm PDMS‐coated fiber for rapid non‐equilibrium SPME at elevated temperatures has interesting potential for high‐throughput analysis of biological samples. 相似文献
20.
Summary A fast and simple headspace SPME sampling method has been developed for quantification of volatile aliphatic aldehydes in
sunflower oil. Analysis has been performed by gas chromatography, on a 30m×0.25 mm i.d. ×0.25 μm CP-Wax 52CB column, with
mass spectrometric detection. Carryover from the SPME fiber could be eliminated by heating the fiber in the injection port
between runs. Response factors of all the compounds were linear for concentrations up to 100 ng μL−1. The slopes of the calibration curves decrease with the amount of saturation of the aldehydes. The average responses for
unsaturated aldehydes were twice as high as those for the saturated variety. Responses for dienes were approximately one order
of magnitude higher than for saturated aldehydes. Depletion of the analyte was examined by repeated extraction from the same
vial. SPME was optimized—after 30 min extraction most components were found to have reached equilibration. The detection limit
for the compounds studied varied between 0.1 and 1 ng μL−1. Distribution constants were determined for ten different aldehydes and Henry's constants were calculated for unsaturated
aldehydes. There was a definite relationship between the response factors and the amount of saturation of the aldehydes.
Presented at: Balaton Symposium on High-Performance Separation Methods, Siófok, Hungary, September 3–5, 1997 相似文献