环境水体中致嗅有机物分析的样品前处理技术研究进展

环境水体中致嗅有机物种类繁多,常见的土霉味物质包括土臭素(GSM)、2-二甲基异茨醇(MIB)、2-甲氧基-3-异丙基吡嗪(IPMP)、2-甲氧基-3-异丁基吡嗪(IBMP)和2,4,6-三氯代苯甲醚(TCA)等,其在水中的质量浓度一般在ng/L ～μg/L水平且嗅阈值较低.该文总结了测定环境水体中痕量土霉味物质的气相色谱-质谱法,并对闭环捕集、吹扫捕集、液液萃取、固相萃取、固相微萃取、液相微萃取和搅拌棒吸附萃取7种样品前处理技术进行了介绍和对比.重点介绍了目前应用最广泛的顶空固相微萃取技术和新发展的液相微萃取、搅拌棒吸附萃取技术在环境水体中致嗅有机物分析中的应用,并展望了致嗅有机物的分析方法.     

顶空固相微萃取-气相色谱-质谱法同时测定饮用水源水中24种VOCs

建立了同时测定饮用水源水中24种挥发性有机物(VOCs)的顶空固相微萃取-气相色谱-质谱法.用75 μm CarboxenTM-Polydimethylsiloxane(CAR-PDMS)固相微萃取柱顶空萃取水样中的VOCs,VOCs用气相色谱-质谱联用仪检测,采用内标法定量.对萃取柱涂层、样品盐度、萃取温度和萃取时间等样品前处理条件进行了优化,VOCs的检出限在0.03～0.31 μg/L之间,线性相关系数r＞0.996(二氯甲烷和三氯甲烷除外).对饮用水源水实际水样0.50μg/L和1.00 μg/L两个加标浓度水平的回收率进行了测定,三氯甲烷回收率均值分别为104％和142％,其余VOCs回收率分别为90.0％～120％和88.0％～110％,除二氯甲烷和三氯甲烷外,其余VOCs测定结果的相对标准偏差均小于15.0％(n=6).该方法适用于饮用水源水中挥发性有机物的监测分析.     

固相萃取-分散液液微萃取-柱前衍生法测定水样中痕量雌激素

建立了碳纳米管的固相萃取-分散液液微萃取-柱前荧光衍生化(SPE-DLLME-PFD)测定水体中痕量雌三醇(E3)、双酚A(BPA)、17α-乙炔基雌二醇(EE2)及17β-雌二醇(E2)的高效液相色谱方法.采用中心复合设计和响应曲面法分析并优化SPE、DLLME及PLD条件,最佳条件为210 mL水样以2.0 mL/min的流速过固相萃取柱(碳纳米管量30 mg),甲醇洗脱,氮气浓缩并定容至0.6 mL(分散剂),将100 μL C6MIM[PF6]与分散剂的混合液注入到NaCl含量为25％的2.0 mL去离子水中,离心,移取20 μL下层有机相于样品瓶中,与4.0 mg衍生剂混合,在40℃水浴中衍生25 min;用0.1mL甲醇溶解过量的衍生剂颗粒,取20 μL进样分析.在优化条件下.4种雌激素的线性范围为0.05～5.00 μg/L,相关系数R2=0.9966～0.9999;,检出限介于0.13～6.33 ng/L(S/N=3)之间.不同加标浓度条件下,雌激素的加标回收率在83.1％～122.4％范围内(RSD=1.7％～9.6％).在实际水样中E3和BPA检出率较高.与其它方法相比,本方法虽然萃取时间长、水样量大、步骤多,但具有检出限低、操作简便、环境友好等优点.     

自动顶空衍生化固相微萃取法测定啤酒中的老化醛类化合物

采用邻-五氟苯甲基羟胺(PFBOA)衍生,顶空固相微萃取(HS-SPME)和气相色谱质谱(GC-MS)测定啤酒中2-甲基丁醛、3-甲基丁醛、反-2-壬烯醛等8种老化醛类化合物.顶空固相微萃取采用65 μm PDMS/DVB纤维,先用纤维吸附PFBOA溶液,再将纤维插入装有2 mL啤酒的20 mL顶空进样瓶的顶空中在60 ℃萃取60 min,衍生和萃取都在自动进样器中进行.采用GC-MS检测,特征离子为m/z 181.8种羰基化合物在0.2～500 μg/L范围内线性关系良好,相关系数在0.990以上.检测样品的相对标准偏差为1.0%～15.7%,回收率为88%～103%.同时研究并讨论了萃取纤维、萃取温度、萃取时间、样品体积等因素对醛类萃取量的影响.该方法可用于啤酒保鲜期研究和产品质量控制.     

固相萃取-毛细管气相色谱法测定生活饮用水中16种硝基苯类化合物

建立了生活饮用水中16种硝基苯类物质的固相萃取-毛细管气相色谱-电子捕获检测方法.实验优化了色谱柱、升温程序等色谱条件,并对影响固相萃取效果的主要因素(萃取小柱、洗脱剂和洗脱体积)进行了考察.水样中16种硝基苯类物质经Oasis HLB固相萃取柱吸附、正己烷-丙酮(3∶1,V/V)洗脱后,采用DB-1701毛细管气相色谱柱程序升温分离、ECD检测,在33 min内完成所有待测组分的测定.16种硝基苯类组分在各自的线性范围内相关系数r≥0.998,方法的检出限为0.01 ～0.77 μg/L(S/N=3),定量限为0.03 ～2.57 μg/L(S/N=10),日内精度和日间精度分别在1.0％ ～ 3.8％和2.3％～4.8％间,样品加标回收率为83.6％～ 111.8％,加标样品的RSD为1.2％ ～5.1％.应用本方法对50份水样进行了分析,结果表明,本方法准确、灵敏、快速,适用于水质的常规分析,可为水样中硝基苯类物质的污染评价提供技术支持.     

溶胶-凝胶富勒烯固相微萃取-气相色谱法测定塑料水浸泡液中多种邻苯二甲酸二酯

利用新型溶胶-凝胶富勒烯涂层,结合顶空固相微萃取-气相色谱法-FID检测,对PVC塑料制品在水溶液浸泡液中的12种邻苯二甲酸二酯进行了分析和测定,其检出限为0.097～3.646 μg/L;回收率为87.9%～107%;RSD<8%.对12种邻苯二甲酸二酯类增塑剂的固相微萃取条件和色谱条件进行了优化,并与商用固相微萃取聚二甲基硅氧烷(PDMS)探头的性能进行了比较.本方法应用于PVC玩具及PVC餐垫样品的分析,结果令人满意.     

分散液液微萃取-气相色谱-质谱分析葡萄酒中单萜醇

采用分散液液微萃取与气相色谱-质谱(GC-MS)联用技术建立了葡萄酒中单萜醇(α-萜烯醇、芳樟醇、香叶醇、香茅醇)的分析方法.考察萃取剂与分散剂的种类和体积、超声和离心时间、盐的加入量、酒样中乙醇含量等因素对萃取效率的影响,确定最佳萃取条件为:在10 mL葡萄酒样中加入2,6-二叔丁基-4-甲基苯酚(BHT)作为内标,再加入100 μL四氯化碳与500 μL丙酮,超声3 min(40 MHz),再离心10 min(5000 r/min)后吸取有机相进行GC-MS分析.用此条件检测4种单萜醇,线性范围为10 ～ 300 μg/L,相关系数均大于0.996,检出限为6～8μg/L.实际葡萄酒样加标回收率为90.8％ ～96.1％,相对标准偏差为4.8％～5.6％(n=6).本方法具有操作简单、快速、灵敏、低成本、环境友好等特点,非常适合大批量样品分析.     

三相中空纤维膜液相微萃取-高效液相色谱法测定水中痕量双酚A

建立了三相中空纤维膜液相微萃取-高效液相色谱(HF-LPME-HPLC)方法,用于分析测定水中痕量双酚A的含量.设计了三相中空纤维膜液相微萃取系统,优化的HP-LPME最佳萃取条件为:萃取剂为正辛醇,接受相NaOH浓度为0.09 mol/L,样品溶液pH=4.0,NaC1加入量为30 g/L,搅拌速度为900 r/min,萃取时间为60 min.萃取后取20 μL接受相进行色谱分析.在最佳萃取条件下,方法的线性范围为0.5～200 μg/L(r＞ 0.999),检出限(信噪比为3)为0.2 μg/L;富集因子为241;方法RSD＜3.2％ (n=3).在实际环境水样中添加5,20和50μg/L的双酚A标准物质,加标平均回收率为92.8％～101.9％.表明本方法可用于水中痕量双酚A的快速准确测定.     

聚吡咯-离子液体固相微萃取涂层的电沉积制备及其在苯类化合物气相色谱检测中的应用

在0.1 mol/L吡咯-0.1 mol/L对甲苯磺酸-4g/L 1-丁基-3-甲基咪唑四氟硼酸盐水溶液中,通过循环伏安法在不锈钢丝表面制备了新型聚吡咯-离子液体(Polypyrrole-ionic liquid,PPY-IL)涂层.此涂层呈菜花状结构,粒度比PPY小.以5种苯类化合物(即1,2-二甲苯、1,2,4-三氯苯、1,2-二氯苯、1,2,4-三甲苯和1,3,5-三甲苯)为目标分析物,对所得萃取头性能进行了考察.在优化的实验条件(萃取温度:50℃；萃取时间:40 min;搅拌速率:600 r/min; NaCl浓度:0.2 g/mL)下,对这些苯类化合物进行顶空固相微萃取-气相色谱检测,其线性范围为0.6～800 μg/L,单根多次萃取的相对标准偏差小于4.5％(n=5),多根萃取头平行萃取的相对标准偏差为4.5％～12.4％(n=5).PPY-IL萃取头有良好的稳定性,在使用150次后萃取性能仅有很小的变化；在温度升至290℃时不分解.与聚吡咯和聚二甲基硅氧烷萃取头相比,本萃取头对这些苯类化合物有更高的萃取能力.     

顶空固相微萃取谱-气相色谱-质谱联用测定饮用水中6种致嗅化合物

采用顶空固相微萃取谱-气相色谱-质谱联用法对饮用水中2-甲基异茨醇、土味素、2-甲氧基-3-异丙基吡嗪、2-甲氧基-3-异丁基吡嗪、2,4,6-三氯苯甲醚和2,3,6-三氯苯甲醚共6种致嗅化合物进行了分析。通过对固相微萃取纤维的类型、解吸附时间、NaCl溶液浓度、溶液pH、顶空温度、转速、顶空时间等顶空条件及GC-MS条件的优化,建立了一次性顶空固相微萃取快速测定饮用水中6种致嗅化合物的方法。采用0.10 mol/L的NaOH溶液将水样调至pH 6.0。以DVB/Carboxen/PDMS涂层的固相微萃取纤维头对20 mL添加了NaCl溶液浓度为0.3 g/mL的水样于70℃水浴顶空萃取25 min。被萃取的致嗅化合物于250℃解吸附4 min供GC-MS分析。6种致嗅化合物在0.25～100 ng/L范围内线性关系良好(R>0.986),检出限低于0.1 ng/L。对实际水样进行分析,低、中、高3种不同浓度的加标回收率为93.0%～106.6%,相对标准偏差为3.0%～6.6%(n=6)。该分析方法可对饮用水中6种致嗅化合物进行同时监测。     

Analysis of Dichlorobenzene in Water by Solid‐Phase Microextraction

The solid‐phase microextraction (SPME) technique using a 100 μm film polydimethylsiloxane (PDMS) coated fiber has been examined with the aim to determine dichlorobenzene in aqueous samples. The feasibility of SPME‐GC‐ECD analysis has been evaluated. Absorption time of 30 min was selected and 1 min was long enough for complete desorption of the analytes in the injection port of the gas chromatograph. Linear ranges from 0.03 to 5 μg/L and method detection limits between 7 and 9 ng/L for dichlorobenzenes were obtained. The relative standard deviations were less than 12% for a spiking level of 3 μg/L. The proposed method was applied to determine dichlorobenzenes in spiked deionized water, ground water, and in industrial effluent samples.     

Determination of Herbicides in Natural Waters Using Solid Phase Microextraction (SPME) and Gas Chromatography Coupled with Flame Thermionic and Mass Spectrometric Detection

Abstract

This study develops a method for solid phase microextraction (SPME) of ten widespread herbicides from water. The selected herbicides belong to different chemical groups are EPTC, molinate, propachlor, trifluralin, atrazine, propazine, terbuthylazine, prometryne, alachlor. Their determination was carried out by gas chromatography with flame thermionic and mass spectrometric detection. To perform the SPME, two types of fibre have been assayed: Carbowax-divinylbenzene (CW-DVB) of 65 μm thickness and polydimethylsiloxane-divinylbenzene (PDMS-DVB) of 65 μm thickness. The main factors affecting the SPME process such as pH, ionic strength, methanol content, memory effect, stirring rate and adsorption-time profile were studied. The method was applied to spiked natural waters such as ground water, sea water, lake water and river water in a concentration range of 0.1 to 10 μg/L. Limits of detection with each of the detectors were determined to be 1 – 20 ng/L in PDMS-DVB and 2–20 ng/L CW-DVB fibres. The recoveries of herbicides compared to distilled water were in relatively high levels 78.3–127.3 % and the average r² values of the calibration curves were above 0.99 for all the analytes. The SPME conditions were finally optimized in order to obtain maximum sensitivity and samples were applied for the trace-level determination in river water samples originating from Ioannina region (Greece).     

一次性固相微萃取-高效液相色谱法测定环境水样中的3种多环芳烃

以涂有聚二甲基硅氧烷(PDMS)的石英光导纤维作为固相微萃取纤维,建立了一次性固相微萃取与高效液相色谱联用测定环境水样中的菲、荧蒽和屈3种多环芳烃(PAHs)的方法。实验考察了解吸时间、萃取时间、搅拌速度、盐效应以及样品溶液pH值对萃取效率的影响,优化得到的萃取和解吸条件为: 于60 mL样品溶液中放入两段萃取纤维(1.5 cm)和1.2 g氯化钠,在1200 r/min搅拌速度下萃取60 min,取出萃取纤维并转入120 μL甲醇中密封静置解吸24 h后,取20 μL解吸液进行液相色谱测定。该方法对于菲、荧蒽和屈的检出限分别为0.17、0.17和0.08 μg/L;精密度(以测定0.5 μg/L PAHs标准溶液6次的相对标准偏差计)小于8%;实际样品中3种PAHs的加标回收率为80.0%～107%。该方法快速简便,纤维一次性使用,克服了污染物在纤维上残留的问题。     

碳纳米管顶空固相微萃取测定水中的多溴联苯醚

建立了顶空固相微萃取联结气相色谱-电子捕获检测器（HS-SPME-GC-ECD）测定水中多溴联苯醚的方法。制作了多壁碳纳米管涂层固相微萃取探头。优化了萃取时间,萃取温度,搅拌速度,顶空体积,溶液的pH,离子强度及有机溶剂等影响萃取效率的各种因素。比较了室温和100 ℃顶空萃取和直接萃取的效率。结果表明,室温下直接萃取比顶空萃取的效率高2-4倍,而在100 ℃时顶空萃取比直接萃取的效率高1-8倍。除BDE-154外,无论直接萃取还是顶空萃取,100 ℃时的萃取效率均高于室温。方法的线性范围50-1600 ng/L,相关系数为0.995-0.998,5种多溴联苯醚的最低检出限（S/N=3）为1.14-16.25 ng/L,相对标准偏差（RSD%,n=5）小于10%。本方法用于真实水样的测定,回收率为74.2%-98.7%。     

Determination of bisphenol A in water by isotope dilution headspace solid-phase microextraction and gas chromatography/mass spectrometry without derivatization

The original solid-phase microextraction (SPME) fibers use an epoxy resin adhesive that releases bisphenol A (BPA) during thermal desorption of the fiber. This adversely affects the method detection limit and accuracy when these products are used for the determination of BPA. In this work, 5 new metal alloy SPME fibers that do not use epoxy resins were compared for the extraction of BPA in water. The performance of the optimum SPME fiber with 60 microm carbowax-polyethylene glycol coating for the headspace SPME of BPA in water was investigated systematically under different extraction conditions. Salt was found to increase the partitioning of BPA from water into the headspace until saturation was reached. Partitioning of BPA from water into the headspace also increased at higher extraction temperatures, as did longer extraction times. However, extraction of BPA from water onto the SPME fiber was not improved for solutions adjusted to pH 2 compared to the unadjusted neutral solutions. The new BPA method showed good linearity over the concentration range of 2.5 to 40 microg/L [correlation coefficient (r2) = 0.995] .The method detection limit for BPA was 0.5 microg/L, while the instrument detection limit was as low as 0.05 microg/L. Good repeatability was observed for BPA at levels of 5 and 20 microg/L with relative standard deviation values < 10%. The automated headspace SPME method developed in this work was used to investigate migration of BPA from polycarbonate bottles into water, and levels of BPA in water ranged from 1.7 to 4.1 microg/L.     

Solid‐phase microextraction with a graphene‐composite‐coated fiber coupled with GC for the determination of some halogenated aromatic hydrocarbons in water samples

In this work, a graphene composite was coated onto etched stainless‐steel wire through a sol–gel technique and it was used as a solid‐phase microextraction (SPME) fiber. The prepared fiber was characterized by SEM, which revealed that the fiber had a highly porous structure. The application of the fiber was evaluated through the headspace SPME of five halogenated aromatic hydrocarbons (chlorobenzene, bromobenzene, 1,3‐dichlorobenzene, 1,2‐dichlorobenzene, and 1,2,4‐trichlorobenzene) in water samples followed by GC with flame ionization detection. The main factors influencing the extraction efficiency, including headspace volume, extraction time, extraction temperature, stirring rate, ionic strength of sample solution, and desorption conditions, were studied and optimized. Under the optimum conditions, the linearity of the method ranged from 2.5 to 800.0 μg/L for 1,2,4‐trichlorobenzene and from 2.5 to 500.0 μg/L for chlorobenzene, bromobenzene, 1,3‐dichlorobenzene, and 1,2‐dichlorobenzene, with the correlation coefficients (r) ranging from 0.9962 to 0.9980, respectively. The LODs (S/N = 3) of the method for the analytes were in the range between 0.5 and 1.0 μg/L. The recoveries of the method for the analytes obtained for the spiked water samples at 50.0 and 250.0 μg/L were from 76.0 to 104.0%.     

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%.     

Solid‐phase microextraction based on polyaniline doped with perfluorooctanesulfonic acid coupled to HPLC for the quantitative determination of chlorophenols in water samples

A porous and highly efficient polyaniline‐based solid‐phase microextraction (SPME) coating was successfully prepared by the electrochemical deposition method. A method based on headspace SPME followed by HPLC was established to rapidly determine trace chlorophenols in water samples. Influential parameters for the SPME, including extraction mode, extraction temperature and time, pH and ionic strength procedures, were investigated intensively. Under the optimized conditions, the proposed method was linear in the range of 0.5–200 μg/L for 4‐chlorophenol and 2,4,6‐trichlorophenol, 0.2–200 μg/L for 2,4‐dichlorophenol and 2–200 μg/L for 2,3,4,6‐tetrachlorophenol and pentachlorophenol, with satisfactory correlation coefficients (>0.99). RSDs were <15% (n = 5) and LODs were relatively low (0.10–0.50 μg/L). Compared to commercial 85 μm polyacrylate and 60 μm polydimethylsiloxane/divinylbenzene fibers, the homemade polyaniline fiber showed a higher extraction efficiency. The proposed method has been successfully applied to the determination of chlorophenols in water samples with satisfactory recoveries.     

Determination of Se4+ in drinkable water by solid-phase microextraction and gas chromatography/mass spectrometry

A method was developed for the selective determination of Se4+ in drinkable water by solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS). Se4+ was selectively derivatized to ethane, 1,1'-selenobis by reaction with sodium tetraethylborate, extracted by the SPME fiber, and determined by GC/MS. Both headspace (HS)-SPME and direct SPME were studied. The method requires only a few milliliters of sample and 20 min for completion. At 2.0 microg/L concentration, the relative standard deviation was 10.1% for HS-SPME and 9.1% for direct SPME. For HS-SPME, the theoretical detection limit was 81 ng/L and 166 ng/L for direct SPME. The recovery rate was 95%. The method was used to determine Se4+ in 10 tap water samples.