活性炭纤维改性对ACF-SPME技术分析多环芳烃的影响

活性炭纤维经改性剂浸渍,水蒸气高温活化后,增大了其对水中多环芳烃的选择性和吸附量,提高了检出限。活性炭纤维活化的最佳条件:在45%磷酸中浸渍6 h,水蒸气中活化30 min,活化温度为500℃。与未改性炭纤维相比,改性后的炭纤维经固相微萃取技术与气相色谱联用测定16种多环芳烃(PAHs),检出限由0.5~50μg/L降至0.01~0.5μg/L,加标回收率由46%~112%增至74%~124%。方法的灵敏度和准确性得到明显的改善,提高了该技术的实际应用价值。     

固相微萃取采样器的开发及其在南海水体多环芳烃检测中的应用

对原有固相微萃取采样器进行改进,并将其用于珠江三角洲西部和东部2个水体基质较复杂的海湾(海陵湾和大亚湾)中16种优控多环芳烃(PAHs)的原位采样分析.研究表明,在分析的16种PAHs化合物中,2、3、4环PAHs均可检出,而5、6环PAHs均未检出.萘、芴、菲、荧蒽、芘5种检出化合物中,除萘外,均与文献中对珠江三角洲水体中PAHs的研究浓度无显著性差别.实验测得萘的质量浓度比传统方法的低,主要是因为固相微萃取水体原位采样技术无需有机溶剂参与样品富集过程,避免了有机溶剂对萘测定的干扰.     

在线固相萃取-高效液相色谱法测定水体中的多环芳烃

建立了在线固相萃取-液相色谱测定水体残留的多环芳烃的方法,用于测定自来水中的20种多环芳烃( PAHs)。直接进样1 mL经过过滤的水体样品,其中的被测组分富集在SPE柱( Acclaim PA II,50 mm×4.6 mm,3μm)上,在线完成净化和萃取富集;再通过阀切换将它们转移至分析流路,在Hypersil Green PAH色谱柱(150 mm ×3 mm,3μm)上分离检测。在线固相萃取流路以水和乙腈为流动相,0.4和0.6 mL/min流速梯度富集/萃取和洗脱;分析流路亦以水和乙腈为流动相,0.8 mL/min流速梯度洗脱,采用紫外254 nm检测无荧光效应的苊烯和弱荧光效应的萘,其它的多环芳烃化合物则于不同的荧光检测通道里,在其对应的最大激发/发射波长下灵敏测定。整个分析流程32 min即可完成。20种PAHs的保留时间的相对标准偏差均小于0.2％,色谱峰面积的相对标准偏差均小于1.3％(n=7);在3个浓度数量级范围内峰面积与进样质量浓度的线性相关系数均大于0.9910,0.05μg/L的自来水加标样品的回收率为57％~140％,5μg/L的自来水加标样品的回收率为85％~116％;多数有荧光响应的PAHs的方法检出限均小于0.02μg/L (S/N=3)。     

石墨烯层层键合固相微萃取纤维的制备及对多环芳烃的检测

通过3-巯基丙基三甲氧基硅烷处理银层包裹的不锈钢纤维,得到Si-OH功能化的纤维,氧化石墨烯被层层键合到Si-OH功能化的纤维上,还原氧化石墨烯得到石墨烯层层键合的固相微萃取纤维。该方法制备的新型石墨烯层层键合的固相微萃取纤维具有制备简单,机械性能强,萃取涂层牢固,萃取能力强等优势。建立具有较宽线性范围(5~200μg/L)、较低检测限(0.007~0.09μg/L)的固相微萃取-气相色谱分析方法,用该方法测定河水和雨水中多环芳烃的含量。所制备的新型纤维重现性好、稳定性高、萃取能力强,可实现对多环芳烃的痕量检测。     

自来水中七种多环芳烃的快速测定

多环芳烃（PAH）在环境中分布广、浓度低，空气、土壤和水的样品中均能检出。PAH大都含有致癌和促进致癌的物质及变异性成分。世界卫生组织拟定了饮用水中六种有代表性多环芳烃总的最高可接受浓度为200ng／L。     

十八烷基离子液体杂化固相微萃取整体柱用于检测咖啡中的多环芳烃

以自制的1-十八烷基-3-(γ-三乙氧基硅基丙基)咪唑溴盐离子液体(C18IL)、二苯基二甲氧基硅烷(DDS)和四乙氧基硅烷(TEOS)为功能单体,采用溶胶-凝胶法制备了烷基咪唑基离子液体管内固相微萃取整体柱(C18IL in-tube SPME).以多环芳烃为分析对象,考察了C_(18)IL含量对C_(18)IL in-tube SPME萃取性能的影响,并对萃取条件进行了优化.建立了基于C_(18)IL in-tube SPME-气相色谱(GC-FID)的分析方法,用于检测萘、芴、菲、荧蒽和芘5种多环芳烃.该方法的检出限(S/N=3)为0.007~0.072μg/L,定量限(S/N=10)为0.023~0.24μg/L,日内和日间精密度(RSD)除菲类多环芳烃外均小于10%.将该方法用于检测咖啡中5种多环芳烃,3个不同浓度下的加标回收率为85.79%~103.42%.     

花生壳活性炭固相萃取/超高效液相色谱法测定河水中的18种多环芳烃

建立了固相萃取/超高效液相色谱-二极管阵列检测(SPE/UPLC-PDA)联用技术测定河水中18种痕量多环芳烃(PAHs)的快速分析方法。通过优化固相萃取条件、流动相体系、色谱条件等因素,7 min内实现了18种多环芳烃的高效分离。在0.05~50 mg/L浓度范围内,18种多环芳烃的浓度与对应峰面积呈良好线性关系,相关系数为0.999 1~0.999 9,检出限为0.08~2.03 ng/L,样品加标回收率为74.5%~103.6%,相对标准偏差(RSD,n=6)为0.5%~2.3%。将该方法应用于九龙江流域龙岩段周边水样的检测,结果可靠。该方法简单环保、灵敏准确、操作快速,可显著提高河水中痕量PAHs的分析效率。     

镍钛合金纤维基体表面纳米多孔复合氧化物的可控生长及其对多环芳烃的选择性固相微萃取

采用水热氧化法制备镍钛合金(NiTi)固相微萃取纤维.实验结果表明,在80℃ 的H2 O2溶液中,直接氧化NiTi纤维基体可在其表面原位生长纳米多孔氧化镍/氧化钛复合涂层,其中氧化镍含量显著高于氧化钛含量.与高效液相色谱-紫外检测器(HPLC-UV)检测技术联用,考察了所制备NiTi纤维对典型芳香族化合物的萃取性能.结果表明,富Ni复合氧化物涂层对多环芳烃(PAHs)表现出良好的萃取选择性.在优化实验条件下,方法的线性范围为0.1~400.0 ng/mL,相关系数大于0.999,PAHs的检出限为0.026~0.056 ng/mL.对于50 ng/mL加标水样,单支NiTi纤维日内和日间测量的相对标准偏差(RSDs)分别为4.8%~6.2%和5.4%~6.5%(n=5),使用5支不同批纤维测量的RSDs为6.4%~8.4%.本方法适用于环境水样中PAHs的富集和测定,相对回收率为89.9%~108.5%,RSDs<8.1%.而且,NiTi纤维机械强度高,化学稳定性好,制备过程精密可控.     

固相微萃取-气相色谱串联质谱法检测北京大气细颗粒物中的多环芳烃

采用固相微萃取与气相色谱串联质谱联用,建立了快捷测定大气细颗粒物(PM2.5)中16种优控多环芳烃的方法.目标物先用二氯甲烷富集浓缩,然后用100 μm聚二甲基硅氧烷萃取纤维,通过超声萃取方式,在60℃条件下,萃取30 min.在优化的在多反应监测模式下,方法回收率在56.8％ ～ 106.0％之间,检出限为0.022～0.056 ng/m3.应用此方法检测了清华大学采样点采取的2013年1月1到15日北京PM2.5空气样品中的16种PAHs,实验结果表明,PAHs总质量浓度在290～1812 ng/m3之间,其中四环PAHs的总质量浓度最大(145 ～937 ng/m3),其次是五环PAHs(总质量浓度81.1～664.5 ng/m3),分子质量浓度较高的依次是荧蒽、芘、苯并(b)荧蒽、(蕴)、苯并(a)芘、苯并(k)荧蒽、苯并(a)蒽和菲,PAHs的污染主要来源于化石燃料燃烧和机动车排放.     

Vacuum-assisted headspace solid phase microextraction of polycyclic aromatic hydrocarbons in solid samples

For the first time, Vacuum Assisted Headspace Solid Phase Microextraction (Vac-HSSPME) is used for the recovery of polycyclic aromatic hydrocarbons (PAHs) from solid matrices. The procedure was investigated both theoretically and experimentally. According to the theory, reducing the total pressure increases the vapor flux of chemicals at the soil surface, and hence improves HSSPME extraction kinetics. Vac-HSSPME sampling could be further enhanced by adding water as a modifier and creating a slurry mixture. For these soil-water mixtures, reduced pressure conditions may increase the volatilization rates of compounds with a low K_H present in the aqueous phase of the slurry mixture and result in a faster HSSPME extraction process. Nevertheless, analyte desorption from soil to water may become a rate-limiting step when significant depletion of the aqueous analyte concentration takes place during Vac-HSSPME. Sand samples spiked with PAHs were used as simple solid matrices and the effect of different experimental parameters was investigated (extraction temperature, modifiers and extraction time). Vac-HSSPME sampling of dry spiked sand samples provided the first experimental evidence of the positive combined effect of reduced pressure and temperature on HSSPME. Although adding 2 mL of water as a modifier improved Vac-HSSPME, humidity decreased the amount of naphthalene extracted at equilibrium as well as impaired extraction of all analytes at elevated sampling temperatures. Within short HSSPME sampling times and under mild sampling temperatures, Vac-HSSPME yielded linear calibration curves in the range of 1–400 ng g⁻¹ and, with the exception of fluorene, regression coefficients were found higher than 0.99. The limits of detection for spiked sand samples ranged from 0.003 to 0.233 ng g⁻¹ and repeatability from 4.3 to 10 %. Finally, the amount of PAHs extracted from spiked soil samples was smaller compared to spiked sand samples, confirming that soil could bind target analytes more strongly and thus decrease the readily available fraction of target analytes.     

An aniline-based fiber coating for solid phase microextraction of polycyclic aromatic hydrocarbons from water followed by gas chromatography-mass spectrometry

A fiber coating from polyaniline (PANI) was electrochemically prepared and employed for solid phase microextraction (SPME) of some polycyclic aromatic hydrocarbons (PAHs) from water samples. The PANI film was directly electrodeposited on the platinum wire surface in sulfuric acid solution using cyclic voltammetry (CV) technique. The applicability of this coating was assessed employing a laboratory-made SPME device and gas chromatography with mass spectrometry (GC-MS) for the extraction of some PAHs from the headspace of aqueous samples. Application of wider potential range in CV led to a PANI with more stability against the temperature. The homogeneity and the porous surface structure of the film were examined by the scanning electron microscopy (SEM). The study revealed that this polymer is a suitable SPME fiber coating for extracting the selected PAHs. Important parameters influencing the extraction process were optimized and an extraction time of 40 min at 40 degrees C gave maximum peak area, when the aqueous sample was added with NaCl (20%, w/v). The synthesis of the PANI can be carried out conveniently and in a reproducible manner while it is rather inexpensive and stable against most of organic solvents. The film thickness of PANI can be precisely controlled by the number of CV cycles. The resulting thickness was roughly 20 microm after 20 cycles. At the optimum conditions, the relative standard deviation (RSD) for a double distilled water spiked with selected PAHs at ppb level were 8.80-16.8% (n = 3) and detection limits for the studied compounds were between 0.1-6 pg mL(-1). The performance of PANI was, also, compared with a commercial solid coated-based SPME fiber, carbowax/divinylbenzene (CW/DVB), under similar experimental conditions.     

Solid-phase microextraction and gas chromatography-mass spectrometry for the determination of polycyclic aromatic hydrocarbons in environmental solid matrices

A solid-phase microextraction (SPME) and gas chromatography-mass spectrometry method for determining polycyclic aromatic hydrocarbons (PAHs) in environmental solid matrices is developed. Investigated matrices include seaweed (Undaria pinnatifida and Himanthalia elongata), humic substances (isolated from a wetland out-flow and purchased from Aldrich), and soil. Optimal conditions for a good SPME efficiency of 16 hydrocarbon compounds are obtained using a 100- micro m polydimethylsiloxane fiber directly immersed in aqueous carrier medium. The method is remarkable for presenting short extraction times and considerably high sensitivities. The SPME results obtained by using internal calibration give the total analyte concentration based on the identical partitioning behavior of native and spiked pollutants. The detection limits range from 0.001 to 0.1 mg of PAH per kilogram of dry matrix. SPME external calibration provides information regarding freely dissolved analytes. The detection limits range from 0.001 to 0.05 micro g of PAH per liter of carrier medium. The SPME with external calibration procedure can be applied to measure free concentrations of a target compound spiked into a carrier medium and onto a matrix. Based on a comparison of results obtained for the two samples, the partitioning of the target analyte between the matrix and the carrier medium is calculated.     

Extraction and enrichment of polycyclic aromatic hydrocarbons by ordered mesoporous carbon reinforced hollow fiber liquid‐phase microextraction

A novel microextraction method, ordered mesoporous carbon reinforced hollow fiber liquid‐phase microextraction coupled with high‐performance liquid chromatography and fluorescence detection, was developed for the determination of some organic pollutants in water samples. Four polycyclic aromatic hydrocarbons (fluorene, anthracene, fluoranthene, and pyrene) were selected to validate this new method. Main parameters that could influence the extraction efficiency such as extraction time, fiber length, stirring rate, the type of the extraction solvent, pH value, the concentration of ordered mesoporous carbon, and salt effect were optimized. Under the optimal extraction conditions, good linearity was observed in the range of 2–1000 ng/L, with the correlation coefficients of 0.9954–0.9986. The recoveries for the spiked samples were in the range of 88.96–100.17%. The limits of detection of the method were 0.4–4 ng/L. The relative standard deviations varied from 4.2–5.9%. The results demonstrated that the newly developed method was an efficient pretreatment and enrichment procedure for the determination of polycyclic aromatic hydrocarbons in environmental water samples.     

Quantitative determination of 16 polycyclic aromatic hydrocarbons in soil samples using solid‐phase microextraction

A method for the determination of polycyclic aromatic hydrocarbons (PAHs) in soil samples using ultrasonic‐assisted extraction with internal surrogates combined with solid‐phase microextraction and GC‐MS has been developed. Five kinds of commercial solid‐phase microextraction fibers, 100 μm PDMS, 30 μm PDMS, 65 μm PDMS/DVB, 50 μm DVB/CAR/PDMS and 85 μm PA, were compared to choose the optimal SPME fiber for extraction of PAHs. One hundred micrometers of PDMS fiber was found to be more suitable for the determination of PAHs due to its wider linear range, better repeatability, lower detection and more satisfactory efficacy than the other fibers. Under the recommended conditions, 100 μm PDMS fiber could provide low nanogram level detection limits with correlation coefficient greater than 0.98. The method was also applied to determine PAHs in a spiked soil sample, obtaining recoveries higher than 79.3%. A field study with naturally contaminated samples from local contaminated sites was carried out. The proposed method was found to be a reliable, inexpensive and simple preparation method for quantitative determination of 16 PAHs in soil samples.     

Determination of polycyclic aromatic hydrocarbons from ambient air particulate matter using a cold fiber solid phase microextraction gas chromatography-mass spectrometry method

Polycyclic aromatic hydrocarbons (PAH) from ambient air particulate matter (PM) were analyzed by a new method that utilized direct immersion (DI) and cold fiber (CF) SPME-GC/MS. Experimental design was used to optimize the conditions of extraction by DI-CF-SPME with a 100μm polydimethylsiloxane (PDMS) fiber. The optimal conditions included a 5min equilibration at 70°C time in an ultrasonic bath with an extraction time of 60min. The optimized method was validated by the analysis of a NIST standard reference material (SRM), 1649b urban dust. The results obtained were in good agreement with certified values. PAH recoveries for reference materials were between 88 and 98%, with a relative standard deviation ranging from 5 to 17%. Detection limits (LOD) varied from 0.02 to 1.16ng and the quantification limits (LOQ) varied from 0.05 to 3.86ng. The optimized and validated method was applied to the determination of PAH from real particulate matter (PM10) and total suspended particulate (TPS) samples collected on quartz fiber filters with high volume samplers.     

Screening method for polycyclic aromatic hydrocarbons in soil using hollow fiber membrane solvent microextraction

A fast, inexpensive screening method for polycyclic aromatic hydrocarbons in soil has been developed. Using hollow fiber membrane solvent microextraction, 8 microl of octane extraction solvent was placed inside a porous, polypropylene fiber. Following an 8 min analyte preconcentration step, 4 microl of extract was injected into a gas chromatograph. Separation was achieved in less than 10 min with a detection limit of 0.13 mg/kg for 2-methylnaphthalene. Results of both spiked and real soil samples are presented.     

Polythiophene/hexagonally ordered silica nanocomposite coating as a solid‐phase microextraction fiber for the determination of polycyclic aromatic hydrocarbons in water

A highly porous fiber coated with polythiophene/hexagonally ordered silica nanocomposite was prepared for solid‐phase microextraction (SPME). The prepared nanomaterial was immobilized onto a stainless‐steel wire for the fabrication of the SPME fiber. Polythiophene/hexagonally ordered silica nanocomposite fibers were used for the extraction of some polycyclic aromatic hydrocarbons from water samples. The extracted analytes were transferred to the injection port of a gas chromatograph using a laboratory‐designed SPME device. The results obtained prove the ability of the polythiophene/hexagonally ordered silica material as a new fiber for the sampling of organic compounds from water samples. This behavior is due most probably to the increased surface area of the polythiophene/hexagonally ordered silica nanocomposite. 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, and desorption temperature and time. Under the optimum conditions, the LOD of the proposed method is 0.1–3 pg/mL for analysis of polycyclic aromatic hydrocarbons from aqueous samples, and the calibration graphs were linear in a concentration range of 0.001–20 ng/mL (R² > 0.990) for most of the polycyclic aromatic hydrocarbons. The single fiber repeatability and fiber‐to‐fiber reproducibility were less than 8.6 and 19.1% (n = 5), respectively.     

基于低共熔溶剂的整体式萃取头的制备及其对湖水中3种多环芳烃的固相微萃取（英文）

采用氯化胆碱-乙二醇低共熔溶剂(DES)作致孔剂,制备了聚(甲基丙烯酸丁酯-乙二醇二甲基丙烯酸酯)[poly(BMA-EDMA)]固相微萃取头,并与超高效液相色谱法(UPLC)结合测定了湖水中的3种多环芳烃(PAHs)。实验与不使用DES致孔剂的固相微萃取头和商品化聚二甲硅氧烷(PDMS)萃取头进行比较,含DES的poly(BMA-EDMA)固相微萃取头的富集效果最好。系统考察了萃取条件(萃取时间、萃取溶剂、解吸时间、解吸溶剂及离子强度)对水样中多环芳烃萃取效率的影响。在最优的实验条件下,3种多环芳烃类化合物(萘、联苯、菲)的线性范围为0.1~6.0 mg/L(r≥0.990 3),检出限为2.1~4.9μg/L,回收率为86.4%~111.3%,相对标准偏差(RSD,n=6)为11.2%~15.1%。该法操作简便,稳定性好,成本低,适用于实际环境水样中多环芳烃类化合物的测定。     

Single layer graphitic carbon nitride-modified graphene composite as a fiber coating for solid-phase microextraction of polycyclic aromatic hydrocarbons

The authors describe a three-dimensional single layer graphitic carbon nitride-modified graphene composite (g-C₃N₄@G) deposited on a stainless steel wire by a sol-gel technique. The coated fiber was applied to direct immersion solid-phase microextraction of trace levels of polycyclic aromatic hydrocarbons (PAHs) from cosmetics samples prior to their determination by gas chromatography with mass spectrometry (GC-MS). Due to π stacking interaction and hydrophobic interaction between the g-C₃N₄@G coating and the analytes (naphthalene, acenaphthene, fluorene, phenanthrene, fluoranthene and pyrene), the fiber displays an excellent adsorption capability for the analytes. Under optimized conditions, the method has a wide linear range, low LODs (from 1.0 to 2.0 ng L⁻¹), good repeatability and high recoveries. It was successfully applied to the determination of PAHs in cosmetics. The g-C₃N₄@G fiber also exhibited good durability.

Schematic of a three-dimensional single layer graphitic carbon nitride-modified graphene composite (g-C₃N₄@G) that was coated onto a stainless steel wire for the direct-immersion solid phase microextraction of trace levels of polycyclic aromatic hydrocarbons prior to gas chromatography-mass spectrometric detection.