Solid phase microextraction(SPME) sampling under turbulent conditions and for the simultaneous collecting of tracer gases

Solid phase microextraction （SPME） is a solvent-flee method of sample collection. SPME is an appealing method for sample collection because it is designed for the sampling of trace level analytes with short sampling times in a variety of environments. Additionally, SPME can be used to directly deliver a sample to a gas chromatograph （GC） for analysis by means of thermal desorption. In this paper, the performance of SPME under dynamic conditions was investigated. Additionally, the competence of SPME sampling for the simultaneous analysis of multiple trace analytes was also evaluated. This work is discussed in the context of underground mine ventilation surveys but is applicable to any industry in which ventilation circuits must be evaluated. The results of this paper showed that the performance of the 100 ~m PDMS SPME fiber was both precise and rapid under dynamic conditions. This SPME fiber was also able to simultaneously collect sulfur hexafluoride （SF6） and perfluoromethylcyclohexane （PMCH） with adequate sensitivity.

Preparation of A New Fiber by Sol-gel Technology in Solid-phase Microextraction (SPME)

The sol-gel technology is applied for the preparation of solid-phase microextraction (SPME) fiber. The fiber demonstrates high thermal stability, efficient extraction rate and the selectivity for non-polar or low-polar analytes. Efficient SPME-GC-FID analyses of benzene- toluene-ethylbenzene-xylenes (BTEXs) and low-polar halocarbon were achieved by the sol-gel coated DSDA-DDBT-TiO2 fiber. Some parameters of the SPME fiber for the determination of halocarbon in aqueous sample were investigated.

Determination of urinary 8-hydroxy-2′-deoxyguanosine by capillary electrophoresis with molecularly imprinted monolith in-tube solid phase microextraction

Urinary 8-hydroxy-2 -deoxyguanosine(8-OHdG) is an excellent marker of oxidative DNA damage.In this study,employing guanosine as dummy template a novel molecularly imprinted(MIP) monolithic capillary column had been synthesized,and that was used as medium of in-tube solid phase microextraction(SPME).Coupled with capillary electrophoresis-electrochemical detection(CE-ECD),the system of extraction and detection of 8-OHdG in urinary sample had been developed.Because of its greater phase ratio combined with conv...

Analysis of α, β, γ-hexachlorocyclohexanes in water by novel activated carbon fiber-solid phase microextraction coupled with gas chromatography—mass spectrometry

A fast and simple method for determination of α, β, γ-hexachlorocyclohexanes (HCHs) in water using activated carbon fiber-solid phase microextraction(ACF-SPME) were studied. Results showed the performance of adsorption and desorption of three HCHs on ACF were excellent. A wide linear range from 10 to 100 μg/L and detection limits of the ng/L level were obtained using ACF-SPME with GC-MS in selected ion monitoring(SIM) acquisition mode. The proposed method was also successfully applied for determination of three HCHs in tap water. Compared to commercial fibers, ACF showed some advantages such as better resistance to solvents, higher thermal stability, longer lifetime and lower cost. The data demonstrated that GC-MS with ACF-SPME is well suitable for the analysis of HCHs in water.

Determination of Aromatic Components of Rosa davurica Pall. by Headspace Solid Phase Microextraction Combined with GC-MS

[Objectives] To determine the aromatic components of Rosa davurica Pall. [Methods] 42 kinds of aromatic components were identified from the flowers of R. davurica by headspace solid phase microextraction( HS-SPME) combined with gas chromatography-mass spectrometry( GC-MS). The main compounds were alcohols( 54. 88%) and aldehydes( 19. 55%). [Results] The top five components with the highest relative content were phenylethyl alcohol( 12. 69%),geraniol( 9. 85%),citronellol( 8. 80%),nerol( 7. 84%) and 2-n-pentylfuran( 7. 45%). [Conclusions] Headspace solid phase microextraction( HS-SPME) combined with gas chromatography-mass spectrometry( GC-MS) can provide basis for further development and utilization of R. davurica.

Solid phase microextraction chemical biopsy tool for monitoring of doxorubicin residue during in vivo lung chemo-perfusion

Development of a novel in vivo lung perfusion(IVLP)procedure allows localized delivery of high-dose doxorubicin(DOX)for targeting residual micrometastatic disease in the lungs.However,DOX delivery via IVLP requires careful monitoring of drug level to ensure tissue concentrations of this agent remain in the therapeutic window.A small dimension nitinol wire coated with a sorbent of biocompatible morphology(Bio-SPME)has been clinically evaluated for in vivo lung tissue extraction and determination of DOX and its key metabolites.The in vivo Bio-SPME-IVLP experiments were performed on pig model over various(150 and 225 mg/m^(2))drug doses,and during human clinical trial.Two patients with metastatic osteosarcoma were treated with a single 5 and 7 μg/mL(respectively)dose of DOX during a 3-h IVLP.In both pig and human cases,DOX tissue levels presented similar trends during IVLP.Human lung tissue concentrations of drug ranged between 15 and 293 μg/g over the course of the IVLP procedure.In addition to DOX levels,Bio-SPME followed by liquid chromatography-mass spectrometry analysis generated 64 metabolic features during endogenous metabolite screening,providing information about lung status during drug administration.Real-time monitoring of DOX levels in the lungs can be performed effectively throughout the IVLP procedure by in vivo Bio-SPME chemical biopsy approach.Bio-SPME also extracted various endogenous molecules,thus providing a real-time snapshot of the physiology of the cells,which might assist in the tailoring of personalized treatment strategy.

Comparison of Headspace Solid-Phase Microextraction with Simultaneous Steam Distillation Extraction for the Analysis of the Volatile Constituents in Chinese Apricot

Volatile constituents in fully mature fruits of apricot （Prunus armeniaca L.） cultivar Xinshiji were extracted using headspace solid-phase microextraction （HS-SPME） and simultaneous steam distillation extraction （SSDE） and then analyzed using capillary gas chromatography and gas chromatography-mass spectrometry. A total of 70 components were identified by HSSPME, including 20 esters, 19 hydrocarbons, 5 alcohols, 5 ketones, 4 acids, 4 lactones, 3 aldehydes, and 10 miscellaneous components, with the esters being the dominant constituent. On the basis of the odor unit values, it is believed that the following compounds probably contributed to the fresh apricot odor： hexyl acetate, β-ionone, butyl acetate, （E）-2-hexenal, linalool, limonene, γ-decalactone, and hexanal. A total of 49 components were also detected by SSDE, including 13 hydrocarbons, 9 alcohols, 7 aldehydes, 9 esters, 4 ketones, 4 lactones, 2 acids, and 1 miscellaneous component, of which the monoterpene alcohols were the dominant constituents. It could be judged from the odor unit values that the following compounds were the major contributors to boiled apricot aroma： β-ionone, linalool, hexyl acetate, γ-dodecalactone, γ- decalactone, （E）-2-hexenal, hexanal, γ-octalactone, phenylacetaldehyde, butyl acetate, limonene, α-terpineol, and δ-decalactone. The results show that HS-SPME is a simple, rapid, and solvent-free method, which is an alternative to the classical SSDE.

A novel fiber coating for solid phase microextraction and its application for the extraction of n-alkane from aqueous sample

Base on the previous work in laboratory, a novel polyaniline doped with polydimethylsiloxane coating was developed on a stainless steel wire for solid phase microextraction（SPME） by electroplating method. This electroplating method not only has advantages of ease preparation and simple equipments required, but also increases the lifetime of the SPME fiber. The composite fiber（polyaniline/ polydimethylsiloxane（PANI/PDMS）） was evaluated by analyzing n-tridecane, n-tetradecane and n-pentadecane in aqueous sample. The new fiber coating showed comprehensive abilities to extract alkanes compounds. The relative standard deviations were found to be 6.8%-10.33%.

Preparation of polypyrrole/nanosilica composite for solid-phase microextraction of bisphenol and phthalates migrated from containers to eye drops and injection solutions

This paper describes the electrodeposition of polyphosphate-doped polypyrrole/nanosilica nano-composite coating on steel wire for direct solid-phase microextraction of bisphenol A and five phthalates. We optimized influencing parameters on the extraction efficiency and morphology of the nanocomposite such as deposition potential, concentration of pyrrole and polyphosphate, deposition time and the nanosilica amount. Under the optimized conditions, characterization of the nanocomposite was inves-tigated by scanning electron microscopy and Fourier transform infra-red spectroscopy. Also, the factors related to the solid-phase microextraction method including desorption temperature and time, extrac-tion temperature and time, ionic strength and pH were studied in detail. Subsequently, the proposed method was validated by gas chromatography-mass spectrometry by thermal desorption and acceptable figures of merit were obtained. The linearity of the calibration curves was between 0.01 and 50 ng/mL with acceptable correlation coefficients (0.9956-0.9987) and limits of detection were in the range 0.002-0.01 ng/mL. Relative standard deviations in terms of intra-day and inter-day by five replicate analyses from aqueous solutions containing 0.1 ng/mL of target analytes were in the range 3.3%-5.4% and 5%-7.1%, respectively. Fiber-to-fiber reproducibilities were measured for three different fibers prepared in the same conditions and the results were between 7.3% and 9.8%. Also, extraction recoveries at two different concentrations were ≥96%. Finally, the suitability of the proposed method was demonstrated through its application to the analysis of some eye drops and injection solutions.

Integration of GC-MS Based Non-Targeted Metabolic Profiling with Headspace Solid Phase Microextraction Enhances the Understanding of Volatile Differentiation in Tobacco Leaves from North Carolina, India and Brazil

In this report, gas chromatography-mass spectrometry (GC-MS) based non-targeted metabolomics is used to develop appropriate headspace solid phase microextractions (HS-SPME) to enhance the understanding of volatile complexity of flue-cured tobacco leaves. Non-targeted metabolic profiling of GC-MS shows that the extraction condition of HS-SPME at 100?C for 30 min provides a better metabolite profile than other extraction conditions tested. GC-MS and principal component analyses (PCA) show that among five types of fibers tested, 100 μm polydimethylsiloxane (PMDS), 65 μm polydimethylsiloxane/divinylbenzene (PMDS/DVB) and 75 μm carboxen/polydimethylsiloxane (CAR/ PMS) provide a better reproducible metabolite profile. Based on an appropriate PDMS extraction condition optimized, we use GC-MS analysis and PCA to compare metabolite profiles in flue-cured leaves of tobacco plants grown in North Carolina, India and Brazil, respectively. The resulting data of PCA show that the global metabolic profiles in North Carolina samples are separated from those in Brazil and India samples, two groups of which are characterized by a partially overlapped pattern. Several peaks that were differentially accumulated in samples were annotated to known metabolites by deconvolution analysis, such as norsolanadione, solavetivone and rishtin. Norsolanadione is detected only in Brazil samples. Solavetivone is detected in samples of India and Brazil but not in those of North Carolina. Rishtin is detected in samples of North Carolina and India but not in Brazil samples. These data indicate that not only can a non-targeted metabolic profiling approach enhance the understanding of volatile complexity, but also can identify marker volatile metabolites in tobacco leaves produced in different growth regions.

Flash Evaporation and Headspace Solid-phase Microextraction for the Analysis of the Essential Oils in Traditional Chinese Medicine,Houttuynia Cordata Thunb

We have investigated the use of flash evaporation, headspace solid-phase microextraction (HS-SPME) and steam distillation (SD) as sample concentration and preparation techniques for the analysis of volatile constituents present in Houttuynia cordata Thunb. The samples were analyzed by gas chromatography (GC) and identified by mass spectrometry (MS). Comparison studies were performed. It was found that the results obtained between Headspace solid-phase microextraction HS-SPME and SD techniques were in good agreement. Seventy-nine compounds in Houttuynia cordata Thunb were identified by MS. In flash evaporation, thirty-nine compounds were identified. Discrimination in the response for many constituents studied was not observed, which can be clearly observed in SD and HS-SPME techniques. As a conclusion, HS-SPME is a powerful tool for determining the volatile constitutes present in the Houttuynia cordata.

Application of Phenyl Bonded Mesoporous Silica as A Novel Coating Layer of Solid-phase Microextraction for Determination of Benzo[a]pyrene in Water Samples

Phenyl bonded mesoporous silica (C6H5-MCM-41) was applied as the fiber coating of solid-phase microextraction (SPME). The performance of the fiber coating was discussed coupling to HPLC. Applicability of mesoporous fiber coating was examined for the determination of benzo[a]pyrene (B[a]P) in water samples. The limit of detection (LOD) is 0.28μg·L-1. Good recovery and relative standard deviation (RSD) were obtained.

Sol-Gel-Coated Calix[4]arene Fiber for Solid-Phase Microextraction

5, 11, 17, 23-tetra-tert-butyl-25, 27-diethoxy-26, 28-dihydroxycalix \ arene /hydroxy-terminated silicone oil coated fiber was first prepared and applied for solid-phase microextraction with sol-gel technology. The properties of the new coating were investigated by analysis of benzene derivatives, polycyclic aromatic hydrocarbons and aromatic amines. The fiber is characterized by good sensitivity and selectivity to these aromatics. The fiber has stable performance at a high temperature of 380℃ and after a long solvent immersing, thus its lifetime is very long. It shows good fiber-to-fiber and batch-to-batch reproducibility. Furthermore, broad linear ranges and low detection limits are also its characteristics.

Solid-phase Microextraction with Benzoxy-calix[6]arene Fiber Coupled to Gas Chromatography for the Analysis of Polycyclic Aromatic Hydrocarbons in Water

Headspace solid-phase microextraction（HS-SPME） with sol-gel calix[6]arene-containing fiber followed by gas chromatography with a flame ionization detector was used to examine the composition and distribution of seven polycyclic aromatic hydrocarbons（PAHs） in water. The novel SPME fiber exhibited higher extraction efficiency to PAHs compared with poly（dimethylsiloxane） and other calixarene-containing fibers. Extraction/retention mechanism based on the interactions between calixarenes and PAHs was discussed. Owing to the good selectivity and high extraction capability of this calixarene fiber, low detection limits were obtained in a range of 0.34―6.50 ng/L and the relative standard deviation values were ≤12.3% for all of the analytes. The linear ranges of the proposed method were five orders of magnitude for the tested compounds, with linear correlation coefficients（r） greater than 0.998. The method was applied to the determination of polycyclic aromatic hydrocarbons in nine water sources in Wuhan City, China. Standard addition method was selected for the quantification and the recovery values were in a satisfactory range. Total PAHs concentrations in the nine surface water samples were found to vary between undetectable and 8.840 μg/L with two- and three-ring PAHs predominating.

基于HS-GC-IMS和HS-SPME-GC-MS的蛋白酶对豆粕挥发性风味的影响分析

为研究不同蛋白酶酶解对豆粕挥发性风味成分的影响,选用4种蛋白酶(碱性蛋白酶、中性蛋白酶、木瓜蛋白酶、风味蛋白酶)对豆粕进行酶解,采用顶空-气相色谱-离子迁移谱(Headspace-gas chromatography-ion mobility spectroscopy,HS-GC-IMS)和顶空固相微萃取-气相色谱-质谱(Headspace solid phase microextraction-gas chromatography-mass spectrometry,HS-SPME-GC-MS)联用技术分析不同豆粕酶解物(Soybean meal hydrolysates,SMH)的挥发性风味成分,并结合主成分分析(Principal component analysis,PCA)、热图聚类和正交偏最小二乘判别法(Orthogonal partial least squares-discriminant analysis,OPLS-DA)对不同SMH进行分析。结果表明:碱性蛋白酶、中性蛋白酶、木瓜蛋白酶和风味蛋白酶酶解豆粕的挥发性风味成分存在较大差异。HS-GC-IMS鉴定出84种挥发性成分,筛选得到33种差异风味物质,发现酶解后酮类物质显著降低而醛类、醇类和酯类物质含量明显增加。PCA结果表明不同SMH之间的风味存在显著差异。最终通过OPLS-DA筛选出贡献较大的挥发性化合物,同时构建出可靠的用以鉴别SMH的模型。HS-SPME-GC-MS检测出103种差异风味物质,可用于区分不同SMH,被检出的挥发性组分中醛类、醇类和酮类等化合物为SMH风味的形成做出主要贡献,明晰了部分风味化合物形成的原因。PCA和聚类热图结果表明不同蛋白酶酶解对豆粕的挥发性风味物质的种类和含量有显著影响,其中,风味蛋白酶和木瓜蛋白酶对豆粕的风味改善最为显著。

HS-SPME-GC-MS与ROAV相结合的4种柑橘果皮精油关键香气物质分析

采用顶空-固相微萃取-气相色谱质谱联用法(HS-SPME-GC-MS)对4种柑橘果皮精油挥发性物质的组成和含量进行分析鉴定,结合相对气味活度值(Relative Odor Activity Value,ROAV)对4种柑橘果皮精油中的关键香气成分进行分析,以期为柑橘果皮精油品质评价与发掘特殊香气柑橘精油提供依据。结果表明,4种柑橘果皮精油共鉴定出62种挥发性成分,包括13种单萜、14种倍半萜、5种烷烃、12种醇类、8种醛类、4种酯类、3种酮类、2种醚类和1种酸类。4种柑橘果皮精油均以单萜化合物相对含量最高(83.00%~91.93%)。按照化合物组成,可将4种柑橘分为2个化学类型:柠檬烯/γ-萜品烯型和柠檬烯/3-蒈烯型。ROAV法从4种柑橘果皮精油中筛选出24种关键香气物质,其中北京柠檬果皮精油中风味贡献最大的物质为紫苏醛,关键香气物质共10种;温州蜜柑、酸橙和枳雀果皮精油中风味贡献最大的物质均为芳樟醇,关键香气物质分别为12种、20种和20种。这些关键香气物质对柑橘果皮精油的香气品质起着重要的作用。

基于HS-SPME-GC-MS与电子鼻分析芹菜贮藏期间挥发性物质的变化

采用顶空固相微萃取技术结合气相色谱-质谱联用(headspace solid phase microextraction-gas chromatography-mass spectrometry,HS-SPME-GC-MS)和电子鼻技术分析了20.0℃贮藏期间芹菜叶片挥发性物质的组成和含量的变化。结果显示,采用HS-SPME-GC-MS技术从芹菜中共检测到108种挥发性物质,单萜类(43.2%~52.92%)和苯酞类(19.93%~28.97%)为主要组分,其中D-柠檬烯含量丰富(6600.64~48566.12μg/kg)。新鲜芹菜总挥发性物质含量为165682.48μg/kg,贮藏9 d后含量下降了40.92%,单萜类和苯酞类物质分别下降了9.72%和上升了8.98%。OAV分析结果表明芹菜叶片中共有31种OAV>1的特征挥发性物质,0~7 d特征挥发性物质有31种且组成相同,第9 d特征挥发性物质减少至29种,贮藏期间总OAV值呈下降趋势。聚类分析结果表明,0~3 d芹菜叶片以薄荷香和青草香为主,第7 d具有甜香、木香和樟脑香,第9 d后以辛辣和药草气味为主。基于电子鼻检测结果的主成分分析可以清晰区分不同贮藏时间芹菜叶片的香气,基于Pearson相关性分析,引起电子鼻响应值变化的物质主要是芹菜中萜类、醇类、芳香型挥发性物质(r≥0.80,P<0.05)。本研究的结果阐明了贮藏期间芹菜叶片挥发性物质组成和含量的变化规律,为贮藏期间芹菜新鲜度的判断提供了理论基础。

基于电子鼻、HS-SPME-GC-MS和HS-GC-IMS评价不同制油工艺对大豆油品质及风味的影响

为探究不同制油工艺(冷榨法、浸出法、冷榨-浸出法)对三级大豆油品质及风味的影响,测定了大豆油的理化性质及脂肪酸组成,分别采用电子鼻、顶空-固相微萃取-气相色谱-质谱(headspace-solid phase microextraction-gaschromatography-massspectrometry,HS-SPME-GC-MS)法和顶空-气相色谱-离子迁移谱(headspace-gas chromatography-ion mobility spectroscopy,HS-GC-IMS)法鉴定3种豆油中挥发性化合物,并借助聚类热图、主成分分析(principal component analysis,PCA)和正交偏最小二乘判别分析(orthogonal partial least squares-discriminant analysis,OPLS-DA)对3种豆油的挥发性化合物数据进行差异分析。结果表明,冷榨型豆油的水分含量最低,浸出型豆油过氧化值显著偏高且油脂色泽最深;浓香型豆油中亚油酸含量最多,营养价值更高;被检出的挥发性组分中,醇类、醛类以及吡嗪类化合物为豆油风味的形成做出主要贡献,明晰了部分风味化合物形成的原因。最终通过OPLS-DA筛选出45种贡献较大的挥发性化合物,同时构建可靠的用以鉴别浓香型豆油的模型。此外,发现豆油的品质与风味之间存在一定的相关性。

基于HS-SPME-GC-MS分析不同龙眼果酒中香气成分

该研究以龙眼为原料,3种酿酒酵母(LABA、CRI、L-EL)为发酵菌种制备龙眼果酒,采用顶空固相微萃取气质联用(HS-SPME-GC-MS)法对其香气成分进行分析,并结合相对气味活度值(ROAV)评价各香气成分对龙眼果酒总体风味的贡献程度,以确定关键香气成分。结果表明,3种酿酒酵母酿造的龙眼果酒中共检出挥发性风味物质58种,其中,酯类19种、醇类8种、醛类7种、烯类2种、酸类4种、醚类3种、酚类5种、醛酮类6种、呋喃类4种。CRI酵母发酵果酒挥发性风味物质的种类最丰富(43种),酯类物质含量最高(1.54 g/L),关键香气成分(ROAV≥1)有7种,分别为丁酸乙酯、己酸乙酯、庚酸乙酯、辛酸乙酯、水杨酸甲酯、丁二酸二乙酯、苯乙酸乙酯。因此,酵母CRI更适合酿造龙眼果酒。

HS-SPME-GC-MS鉴定不同采收程度霞晖水蜜桃的风味物质变化

风味物质常用来评价桃果实的品质,香气成分不仅能反映果实的风味特征和品质,还能体现果实的成熟度。利用顶空固相微萃取(HS-SPME)结合气相色谱-质谱联用仪(GC-MS)鉴定了霞晖水蜜桃果实可挥发性风味物质,并针对水蜜桃S形成熟曲线,成熟后期快速软化的特点,选择后期外观差异较小且按照售卖经验分类为可采摘与不可采摘两类水蜜桃进行差异分析,寻找其特征差异物质。本研究共分离得到45种风味物质,主要包括苯甲醛、壬醛、十一醛、芳樟醇、2-乙基己醇、正癸醇、1-十一醇、γ-癸内酯、γ-十二内酯、辛酸乙酯和壬酸等。不可采收的霞晖水蜜桃果实和可采收的霞晖水蜜桃果实中差异特征风味物质分别是苯甲醛(35.84%)降低和γ-癸内酯(17.81%)升高。总体来看,醛类和内酯类化合物对霞晖水蜜桃果实香气的贡献值得关注。上述研究以期为水蜜桃精准采摘、智慧化采摘提供科学依据。