Solid-phase Microextraction Extraction Efficiency Research Articles

Research progress on the application of derived porous carbon materials in solid-phase microextraction

固相微萃取是一种集采样、萃取、富集和进样于一体的样品前处理技术,其萃取效果与涂层材料密切相关。多孔碳材料具有比表面积大、多孔结构可控、活性位点多和化学稳定性好等优点,广泛应用于电池、超级电容器、催化、吸附和分离等领域,也是一种热门的用作固相微萃取探针的涂层材料。衍生多孔碳材料因种类丰富、可设计性强被广泛研究,研究主要集中在对衍生多孔碳材料的结构优化方面。但是衍生多孔碳材料在固相微萃取中的应用还存在如下问题:(1)共价有机框架衍生多孔碳材料的制备已取得较大进展,但将其应用于固相微萃取领域的研究仍较少;(2)有待进一步明确制备出的衍生多孔碳材料用作固相微萃取涂层表现出优异提取能力的机理;(3)有待进一步深入研究将衍生多孔碳材料用作固相微萃取涂层以实现对不同物理化学性质污染物的广谱高灵敏度分析。文章综述了近3年衍生多孔碳材料在固相微萃取中的应用研究,并展望了未来衍生多孔碳材料在固相微萃取中的研究前景。引用文献共56篇,主要来源于Elsevier。

Application of portable gas chromatography–mass spectrometer for rapid field based determination of TCE in soil vapour and groundwater

The application of portable chromatography–mass spectrometer (GC–MS) is restrained by its detection limits without the development of proper sample pre-concentration methods. The primary focus of this paper is to introduce a practical field measurement methodology for the analysis of volatile organic compounds (VOCs) in soil vapour and groundwater using a portable gas (GC–MS)system for application to in situ assessment of vapour intrusion from VOC contamination. A solid-phase micro-extraction (SPME) technique was applied for sample pre-concentration before the GC–MS​ measurement. Practical in-field soil gas SPME sampling methods have been developed to optimise the SPME extraction efficiency to then ultimately improve the detection limits of portable GC–MS. An Australian site impacted by a chlorinated VOC, trichloroethylene (TCE), was the subject of the case study. To rapidly assess soil vapour samples in subsurface soil, in-house-developed retractable soil vapour sampling probes (SVSPs) were installed at the site in clusters at depths of 1 m, 2 m and 3 m below ground level at each sampling location. Use of the SVSPs for sampling enabled the generation of a three-dimensional map and distribution contours for TCE concentrations using the in situ measurement results of a portable GC–MS analysis for vapour intrusion investigation. The results of the portable GC–MS​ analysis were compared with the results from conventional USEPA methods, such as TO-15 and Method 8265 for soil vapour and groundwater samples, respectively. This work demonstrates that the developed methodology of using a portable GC–MS system has the capability for in-field quantitative analysis of VOCs for rapid contaminated site vapour intrusion assessment.

Establishment of the Volatile Signature of Wine-Based Aromatic Vinegars Subjected to Maceration.

The flavoring of vinegars with aromatic fruits and medicinal herbs is a practice with increasing trend mostly in countries with oenological tradition, resulting in a product of improved quality and consumer attractiveness. This study was directed towards the evaluation of the impact of the maceration process on the volatile signature of wine-based aromatic vinegars (WBAVs). The evaluation was performed using solid phase microextraction (SPME) combined with gas chromatography combined with mass spectrometry (GC-MS). Experimental parameters influencing headspace solid (HS)-SPME extraction efficiency, were optimized using an univariate experimental design. The best results were achieved using a polydimethylsiloxane (PDMS) fiber, 10 mL of vinegar sample, at 50 °C for 30 min of extraction. This way One hundred and three volatile organic compounds (VOCs), belonging to different chemical families including ethyl esters (37), higher alcohols (20), fatty acids (10), terpenoids (23), carbonyl compounds (six), lactones (five) and volatile phenols (two), were identified in wine vinegar (control) and WBAV. As far as we know, 34 of these VOCs are reported for the first time in macerated vinegars. Higher alcohols and lactones are the major chemical families in WBAV macerated with apple, whereas terpenoids are predominant in WBAV macerated with banana. The obtained data represent a suitable tool to guarantee the authenticity and genuineness of WBAV, as well as to promote the production of WBAV with improved sensorial and organoleptic properties. To the best of our knowledge, there are no reported studies dealing with the volatile signature of WBAV enriched with banana, passion fruit, apple and pennyroyal.

A salting out system for improving the efficiency of the headspace solid-phase microextraction of short and medium chain free fatty acids

Given the importance of short and medium chain free fatty acids (FFAs) in several fields, this study sought to improve the extraction efficiency of the solid-phase microextraction (SPME) of FFAs by evaluating salting out agents that appear promising for this application. The salts ammonium sulfate ((NH4)2SO4) and sodium dihydrogen phosphate (NaH2PO4) were tried on their own and in combination (3.7/1), in four different total amounts, as salting out agents in the headspace–SPME–gas chromatographic (HS–SPME–GC) analysis of the FFAs from acetic acid (C2) to decanoic acid (C10). Their performance in a model system of an aqueous standard mixture of FFAs at a pH of 3.5 was compared to that of the more commonly used sodium chloride (NaCl) and sodium sulfate (Na2SO4). All of the salts and salt systems evaluated, in proper amount, gave improved results compared to NaCl (saturated), which instead gave interesting results only for the least volatile FFAs C8 and C10. For C2–C6, the salt system that gave the best results compared to NaCl was (NH4)2SO4/NaH2PO4, in the highest of the four amounts evaluated, with factor increases between 1.2 and 4.1-fold, and NaH2PO4, between 1.0 and 4.3-fold. The SPME extraction efficiency given by the mixture (NH4)2SO4/NaH2PO4 was also assessed on biological and food samples, confirming that overall it performed better than NaCl.

Determination of organochlorine pesticides in textiles using solid-phase microextraction with gas chromatography–mass spectrometry

Abstract A method based on solid-phase microextraction (SPME) and gas chromatography with mass spectrometry (GC/MS) for the determination of 10 organochlorine pesticides (OCPs) in ecological textiles was described. Commercially available SPME fibers, 100 μm PDMS, 85 μm PA, 65 μm PDMS–DVB, 75 μm CAR/PDMS and 30 μm PDMS were compared and 100 μm PDMS exhibited the best performance to the OCPs. Various parameters affecting the extraction efficiency of SPME were optimized, including extraction time, desorption time, extraction temperature, salinity and pH. The optimized conditions were 40 min extraction at room temperature, 2% NaCl content, pH 6.0, and 4.0 min desorption in GC injector port at 250 °C. Under the optimized conditions, the limits of detections ranged from 0.04 μg L− 1 (dieldrin) to 0.41 μg L− 1 (aldrin) and the RSDs were between 3.2% and 11.3%. The optimized method was then used to analyze 10 OCPs in textile samples, and good relative recoveries were obtained (from 70.0 to 112.6%). This study illustrated the potential applicability of SPME for routine analysis of OCPs in textiles.

Polyparameter Linear Free Energy Models for Polyacrylate Fiber−Water Partition Coefficients to Evaluate the Efficiency of Solid-Phase Microextraction

The fiber-water partition coefficient, K(fw), is decisive for performance of solid-phase microextraction (SPME) techniques in organic chemical analyses. In this study, polyacrylate (PA)-coated fiber was evaluated for its K(fw) values toward diverse neutral organic compounds. Literature K(fw) data were thoroughly evaluated, and additional K(fw) values for 69 compounds were measured in phosphate-buffered saline (PBS) solution at 37 °C. These K(fw) data, spanning over 6 orders of magnitude, were used to construct polyparameter linear free energy relationship (PP-LFER) models. The PP-LFER models fit well to the data with a standard deviation of 0.15-0.23 log units. Additional experiments indicated that the differences in temperature (25 vs 37 °C), electrolyte concentrations (pure water vs PBS), and conditioning methods (heat vs methanol) had only minor influences (<0.3 log units) on K(fw). Using the established PP-LFERs, the SPME extraction efficiency of PA coating toward compounds of differing polarity was evaluated in comparison to poly(dimethylsiloxane) (PDMS) coating. PA exhibited higher extraction capacities for H-bond donor compounds (e.g., phenols, anilines, amides, and many drugs and pesticides) with the estimated K(fw) values being 1-4 log units higher than those of PDMS. Also, PA was shown to be more efficient than PDMS for hydrophobic aromatic compounds.

Application of SPME Based on a Stainless Steel Wire for the Determination of Pyrethroid Insecticide Residues in Water and Soil

In this study, a solid-phase microextraction (SPME) method based on a bare stainless steel wire as the fiber has been developed for extraction and determination of five pyrethroid insecticides (fenpropathrin, cyhalothrin, cypermethrin, fenvalerate and deltamethrin) in water and soil samples. The influences of extraction parameters (extraction time, stirring rate and salt addition) on the SPME extraction efficiency were investigated, and the optimum conditions were applied for the extraction of the target analytes from water samples. The method showed linear behavior ranging from 0.05 to 2 µg L−1 with detection limits of 0.6–1.9 ng L−1 for water analysis. Recoveries were from 71 to 112% for all the target insecticides in water and soil sample, with RSDs from 6.8 to 19.4% (n = 3). The study demonstrated the feasibility of the proposed SPME fiber based on stainless steel wire for the extraction of pyrethroid insecticides in water and soil.

Analysis of chloroacetanilide herbicides in water samples by solid-phase microextraction coupled with gas chromatography–mass spectrometry

A solid-phase microextraction (SPME) method has been developed for the determination of 3 chloroacetanilide herbicides in both fresh and seawater samples. The extracted sample was analyzed by gas chromatography with mass spectrometry detection (GC–MS), and parameters affecting SPME operation including fibre type, sample pH, sample temperature, mixing speed and extraction time have been evaluated and optimized. The amount of dissolved organic matter (DOM) and the salt content both affected SPME extraction efficiency, but the presence of other competitive extractants such as organochlorine pesticides (OCPs) in the matrix showed no insignificance interference. The limit of detection (LOD) for acetochlor, metolachlor and butachlor were 1.2, 1.6 and 2.7 ng L −1, respectively. The recoveries for the herbicides ranged from 79 to 102%, and the linear dynamic range was from 10 to 1000 ng L −1. The developed method has been used to monitor herbicides contaminations in coastal water samples collected around Laizhou bay and Jiaozhou bay in Shandong peninsula, China. The concentrations of acetochlor and metolachlor ranged from undetectable to 78.5 ng L −1 and undetectable to 35.6 ng L −1, respectively. Butachlor was not observed but in only one sample and the concentration is lower than the limit of quantification (LOQ). The concentrations of the three herbicides in this study are low compared to most of the other places reported.

Reevaluation of headspace solid-phase microextraction and gas chromatography–mass spectrometry for the determination of methyl tert-butyl ether in water samples

A headspace solid-phase microextraction (SPME) and gas chromatography–mass spectrometry (GC–MS) method has been reevaluated for the determination of methyl tert-butyl ether (MTBE) in water. Factors affecting method performance were examined. The internal standard, deuterated MTBE, is necessary because it allows normalization of the calibration since the deuterated MTBE and MTBE experience the same extraction efficiency. The method detection limit was 6.6 ng/l, with a linear range up to 160 μg/l. SPME extraction efficiency and detection sensitivity for MTBE decreased in the presence of gasoline matrix. However, reliable measurement of MTBE was possible in the background matrix concentration of 0.97 mg/l gasoline using deuterated internal standard. Reproducibility was 4.5% at the spiking level of 47 ng/l. The average recoveries of MTBE in spiked fountain water, tap water, and snow at 60 ng/l and in spiked rainwater at 580 ng/l ranged from 101 to 105%. The method was successfully applied to the analysis of trace levels of MTBE in various water samples, including rain and snow samples collected in Albany, NY, USA.

Improved Analysis of MTBE, TAME, and TBA in Petroleum Fuel-Contaminated Groundwater by SPME Using Deuterated Internal Standards with GC−MS

An improved method is described for the routine analysis of methyl tert-butyl ether (MTBE), tert-amyl methyl ether (TAME), and tert-butyl alcohol (TBA) in petroleum fuel-contaminated groundwater samples using solid-phase microextraction (SPME) and deuterated internal standards combined with gas chromatography mass spectrometry (GC-MS). Factors affecting method performance (SPME fiber selection, headspace or liquid extraction, extraction time, calibration conditions, salt addition, method sensitivity, and matrix effects) are evaluated using groundwater samples from a chalk aquifer contaminated with petroleum fuel containing MTBE, TAME, and TBA. The detection sensitivity and analytical efficiency of the method was optimized for these compounds using a PDMS-Carboxen fiber, sample NaCl content of 25% (w/v), and extraction time of 30 min. Internal calibration standards (deuterated MTBE and TBA) are necessary to control extraction errors during analysis. SPME extraction efficiency and detection sensitivity for ...

Determination of amines in air and water using derivatization combined with solid-phase microextraction

Solid-phase microextraction (SPME) is a simple, fast, economic and solvent-free sample preparation technique. The selectivity and sensitivity of this technique for the determination of amines in gaseous and aqueous matrices can be significantly improved by coupling derivatization with SPME during sampling. Derivatization has advantages in enhancing coating–gas and coating–water partition coefficients for amines, thus improving SPME extraction efficiency and method sensitivity. For air analysis, 4-nitrophenyl trifluoroacetate effectively derivatized volatile and polar amines into less polar amides in the gaseous phase, with limits of detection (LODs) at the low pg/ml level when gas chromatography–flame ionization detection (GC–FID) was used. For aqueous sample analysis, pentafluorobenzylaldehyde was utilized to convert polar primary amines into their less polar imines directly in aqueous solutions. Derivatization-SPME provided LODs at low ng/ml to pg/ml levels with GC–FID. Compared to direct SPME, derivatization-SPME lowered LODs by two–three orders of magnitude for the analysis of amines in air and aqueous solutions.

Determination of 4-nonylphenol—part 2: Orthogonal array design as a chemometric method for the solid-phase microextraction of 4-nonylphenol in water

Orthogonal array design (OAD) using two-level OA8(27) matrix was employed for the optimization of solid-phase microextraction (SPME) conditions for the determination of 4-nonylphenol (4-NP) in water. The parameters under consideration for the optimization of SPME conditions include: injector port temperature, initial oven temperature, desorption time, and pH. The effect of dissolved humic substances on the extraction efficiency of SPME for the determination of 4-NP was also investigated. The method is capable of parts per billion detection limit with a %RSD of 6.5%. Thus, the SPME approach is suitable for analytical determination of 4-NP in environmental water samples compared to conventional liquid-liquid extraction (LLE) technique. © 1996 John Wiley & Sons, Inc.