顶空/气相色谱-质谱法分析方便面印刷包装材料中挥发性有机物

利用顶空/气相色谱-质谱(HS/GC-MS)联用法对袋装方便面印刷包装材料中7种挥发性有机物(异丙醇、乙酸乙酯、苯、乙酸丁酯、乙苯、间/对二甲苯、邻二甲苯)进行了检测分析.优化的实验参数为:平衡温度80℃,平衡时间40 min.本方法线性关系良好,7种挥发性有机物的相关系数均大于0.9991,检出限为0.004～0.0...     

吹扫捕集-气相色谱分析海水和沉积物中的苯、甲苯、乙苯及二甲苯

单环芳烃苯、甲苯、乙苯和二甲苯（简称BTEX）是石油的重要组分，也是环境中需要重点监测的致癌污染物。本实验建立了动态顶空（吹扫捕集）和光离子化检测器的气相色谱测量海水、沉积物中痕量BTEX的方法。在120—1200ng／L的浓度范围，苯、甲苯、乙苯、间对二甲苯及邻二甲苯标准溶液的检出限分别为6．4、35．2、15．8、12．3、10．7ng／L，相对标准偏差0．9％-6．1％。样品无需预处理，海水中BTEX回收率为93．50％-98．40％。7个渤海表层海水样品中BTEX的浓度均低于140ng／L；海底沉积物中苯、甲苯、乙苯、间对二甲苯及邻二甲苯浓度分别为169—1243、531—1732、1308—5624、237—1136、510—5194ng／L。测量方法和结果对评价环境污染具有重要意义。     

异丙醇-(NH4)_2SO_4-H_2O双水相体系样品前处理结合GC/MS测定化妆品中苯系物

本文用异丙醇-(NH_4)_2SO_4-H_2O双水相体系高效提取化妆品中的苯系物(BTEX,苯、甲苯、乙苯、对二甲苯、间二甲苯和邻二甲苯),结合气相色谱-质谱联用(GC-MS)实现了对化妆品中六种BTEX的快速准确测定。实验主要考察了双水相体系的形成条件,并探讨了双水相体系对BTEX的萃取效率。实验结果表明:异丙醇不仅具有较好的破乳性能,而且对样品中BTEX有较高的提取效率;硫酸铵具有较好的盐析分相作用;化妆品中BTEX的萃取率与异丙醇水溶液的体积分数有关,当双水相体系中水与异丙醇的体积之比约为3∶2时,异丙醇与化妆品中的BTEX可接触充分,萃取率较高。该方法对化妆品中BTEX的测定回收率为81.1~98.2%,检出限为1.1~3.9 ng·g。     

吹扫捕集气相色谱法测定卷烟包装卡纸中苯系物残留

采用吹扫捕集气相色谱法测定卷烟包装卡纸中苯系物残留,并对测试条件进行了优化。所测定的苯、甲苯、乙苯、对二甲苯、间二甲苯、邻二甲苯、苯乙烯等在4.3~900μg.L-1浓度范围具有良好的线性,相关系数均达到0.999 9,检出限为1.0~11.6 ng.g-1,回收率为91.5%~109.2%,重复测定5次的相对标准偏差为1.73%~3.24%。     

气相色谱法测定室内空气中苯系物含量的研究

优化了固体吸附/热解吸-气相色谱法测定室内空气中苯、甲苯、乙苯、对二甲苯、间二甲苯、异丙苯、邻二甲苯和苯乙烯等8种苯系物的方法。结果表明,目标物色谱峰分离度均大于1.5;在10～500 ng范围内,8种苯系物质量与色谱峰面积呈良好的线性,相关系数r为0.999 7～0.999 9;该方法的检出限为0.50～3.48ng,当采气量为2L时,最低检出浓度为0.25×10~(-3)～1.74×10~(-3)mg/m~3,相对标准偏差为1.2%～9.1%(n=6),回收率在94.0%～99.5%之间。该方法分离效果好,灵敏度高,精密度好,结果准确,可用于室内空气中苯系物含量的检测。     

吹扫捕集/气相色谱－同位素比值质谱联用测定水体中痕量苯系物单体碳同位素

建立了吹扫捕集（P&T）/气相色谱－同位素比值质谱（GC/C－IRMS）联用测定水体中痕量苯系物单体碳同位素的方法。优化了吹扫时间、吹扫温度和干吹时间,确定最优吹扫捕集效率,并通过测试不同质量浓度的苯系物水溶液,计算水体中痕量苯系物的检出限。结果表明,在35 ℃下吹扫捕集13 min,干吹时间3 min条件下,水样中苯、甲苯、乙苯、间/对二甲苯、邻二甲苯、苯乙烯、异丙苯的吹扫捕集效率分别为95.0%、90.2%、71.3%、59.1%、69.4%、50.8%和70.1%,7种苯系物单体碳同位素的标准偏差（STD）为0.06‰ ~ 0.29‰。7种苯系物的质量浓度在0.50 ~ 20.00 μg/L范围内与峰面积的线性关系良好,相关系数（r2）为0.998 6 ~ 0.999 5,在各浓度下7种苯系物单体碳同位素值的标准偏差为0.090‰ ~ 0.48‰,进样量及进样方式的差异不会导致碳同位素分馏。水样中苯、甲苯、间/对二甲苯、邻二甲苯和苯乙烯的检出限为1.00 μg/L,乙苯和异丙苯为0.50 μg/L。该方法可以极大提高水体中苯系物单体碳同位素的检出限,结果准确可靠,满足水体中痕量苯系物单体碳同位素分析的需求。     

二次热解吸-气相色谱-质谱法测定聚乳酸线材用于增材制造时产生的有机挥发物

将聚乳酸(PLA)线材在增材制造时产生的有机挥发物(VOCs)收集在自制的气体收集瓶中,并在20℃下稳定10min,在经活性炭过滤好的空气的作用下,用TenaX-TA吸附管采集收集瓶中气体20min,采集的气体经二次热解吸后,以100∶1的分流比进入气相色谱,用DB-5MS色谱柱在程序升温条件下分离,进入质谱检测器测定其中主要的9种VOCs(包括苯、甲苯、苯乙烯、乙苯、乙酸丁酯、邻二甲苯、间二甲苯、对二甲苯和正十一烷)含量。在优化的条件下,9种VOCs的保留时间为5.30～23.63min。结果显示:9种VOCs的质量分别在40～4 000ng(间二甲苯+对二甲苯)和20～2 000ng(其他7种组分)内与其对应的峰面积呈线性关系,检出限(3S/N)为1.1～2.5μg·kg~(-1);对实际样品进行3个浓度水平的加标回收试验,所得回收率为91.2%～103%,测定值的相对标准偏差(RSD,n=6)为2.0%～8.5%;用此方法分析了6种样品,9种组分均有不同程度检出,总VOCs(TVOCs)含量的RSD(n=11)小于10%。     

C_8芳烃异构体+异丙醇体系在333.15K时的过量摩尔Gibbs自由能

采用CP-I型汽液平衡双循环釜,测定了333.15 K时乙苯+异丙醇、邻二甲苯+异丙醇、间二甲苯+异丙醇、对二甲苯+异丙醇四个体系的汽液平衡数据,计算了该温度下四个体系的过量摩尔Gibbs自由能,并对所测数据进行了恒温下热力学一致性检验。用Wilson方程关联了实验数据,拟合精度令人满意。     

同时测定水基胶中乙酸乙烯酯和六种苯系物的方法

本发明公开了一种同时测定水基胶中乙酸乙烯酯和六种苯系物含量的方法,采用N,N-二甲基甲酰胺分散样品,双内标法进行定量,利用顶空–气相色谱–质谱联用仪,于一次进样中对烟用水基胶中的7种化合物进行同时测定;所采用的色谱条件使得苯、甲苯、乙苯、邻二甲苯、间/对二甲苯(间二甲苯和对二甲苯因色谱柱问题,没有分开,但不影响计算结果 )和乙酸乙烯酯目标物和二个内标物异丁醇、2-己酮的色谱峰都分离较好。结果显示,各组分的回归方程相关系数均达到0.999以上,苯系物的定量检出限为0.01~0.02 mg/kg,乙酸乙烯酯的定量检测限为0.10mg/kg,平均相对标准偏差为1.15%~3.75%,加标回收率在88.09%~95.44%,具有快速、准确、重复性好、回收率高等优点,具有良好的实用性。     

海水中痕量苯系物的吹扫捕集/气相色谱质谱联用测定

建立了海水中苯、甲苯、乙苯、对二甲苯、间二甲苯、邻二甲苯以及苯乙烯7种苯系物的测定方法。采用吹扫捕集法对海水中的苯系物进行富集,热解吸后导入气相色谱-质谱仪,并选用选择离子模式(SIM)进行检测。结果表明:在100.0～2 000.0 ng/L范围内7种苯系物浓度与仪器响应值的线性关系良好,相关系数为0.999 6～0.999 8,方法检出限为5.9～10.7 ng/L;两种不同浓度加标水平(250.0、1000.0 ng/L)的平均回收率分别为84%～105%和96%～97%,相对标准偏差(n=6)分别为3.7%～6.5%和2.1%～3.3%。该方法准确、快速,且具有富集效率高、无试剂再污染等优点,适用于海水中痕量苯系物的分析测定。     

Simple analysis of volatile organic compounds (VOCs) in the atmosphere using passive samplers.

A simple analysis of volatile organic compounds (VOCs), such as benzene, toluene, m,p-xylene, and o-xylene, at low levels in the atmosphere was conducted using passive samplers. The methods were applied to analyzing the behavior and origin of VOCs in Kyoto City. The passive samplers were exposed for 7 - 14 days at sampling sites in Kyoto City and for 30 days in the mountains (Mt. Hiei and Mt. Daimonji). Shibata gas-tube samplers packed with activated carbon were used for the determination of VOCs. The absorbed VOCs were extracted into carbon disulfide (CS2) and measured by FID-GC. The determination limits and relative standard deviations for VOCs were 0.3 microg/m3 and 3%, respectively. The samplers were set up at 5 sites in March, 2001 and at 13 stations on Mt. Hiei in November, 2002. The average concentrations of ambient benzene, which were higher than the environmental criterion (3.0 microg/m3), except for those on Mt. Daimonji from March, 2001, to February, 2002, decreased to below 3.0 microg/m3 from March, 2002, to February, 2003. The decrease in ambient benzene may have been due to a decrease in the benzene content in gasoline by the end of 1999, and also by implementation of the Pollutant Release and Transfer Register (PRTR) Act in 2001.     

DEEP CATALYTIC OXIDATION OF BENZENE IN THE PRESENCE OF SEVERAL VOLATILE ORGANIC COMPOUNDS ON METAL OXIDES AND Pt/Al2O3 CATALYSTS

Oxidation of benzene into CO₂ in air has been studied in the temperature range of 300-673 K on supported metal oxides and on 0.7% Pt/Al₂O₃, in the absence and in the presence of several Volatile Organic Compounds (VOCs). On the metal oxides, the deep oxidation of benzene is strongly inhibited in presence of VOCs and O-containing VOCs lead to more toxic VOCs (i.e: acetaldehyde).     

环境污染事故中挥发性有机物快速定量方法

在相同的色谱条件下,分别以内标法和外标法对Restek Volatiles和J＆W DB-624毛细管色谱柱建立了以苯、甲苯和乙苯为标准物质的相对响应因子（RRF）快速定量数据库。其它挥发性有机物可采用RRF平均值进行估算,相对误差在-85．9％～52．3％之间。运用建立的数据库,对实际大气样品进行测定,证明方法可行。     

Multiple headspace solid-phase microextraction for the quantitative determination of volatile organic compounds in multilayer packagings

The theory of multiple headspace solid-phase microextraction (HS-SPME) and a method based on multiple HS-SPME for the quantitative determination of volatile organic compounds (VOCs) in packaging materials is presented. The method allows the direct analysis of solid samples without using organic solvents to extract analytes. Multiple headspace solid-phase microextraction is a stepwise method proposed to eliminate the influence of the sample matrix on the quantitative analysis of solid samples by HS-SPME. Different amounts of packaging and different volumes of standard solution were studied in order to remove a substantial quantity of analytes from the headspace at each extraction and obtain the theoretical exponential decay of the peak area of the four successive extractions and, thus, the total area was calculated from these four extractions. In addition, two fibres were compared: carboxen-polydimethylsiloxane (CAR-PDMS) and divinylbenzene-carboxen-polydimethylsiloxane (DVB-CAR-PDMS), as they showed differences in the linearity of the exponential decay with the number of extractions depending on the compound. The CAR-PDMS fibre was better for the VOCs with a low molecular mass, whereas the DVB-CAR-PDMS fibre was better for the VOCs with a high molecular mass. Finally, the method was characterised in terms of linearity, detection limit and reproducibility and applied to analyse four multilayer packaging samples with different VOCs contents.     

Affinity-based elimination of aromatic VOCs by highly crystalline multi-walled carbon nanotubes

Carbon nanotubes (CNTs) are capable of adsorbing pollutant chemicals. Their adsorptive capacities and adsorbing mechanisms, however, are not fully understood. As-grown CNTs often contain both crystalline and amorphous carbon, and the ratio of carbon types can affect adsorption. In this study, highly crystalline multi-walled carbon nanotubes (HC-MWCNTs) were used as the adsorbent for volatile organic compounds (VOCs) in contaminated air samples. Air containing 23 added VOCs (1,1-dichloroethylene, dichloromethane, trans-1,2-dichloroethylene, cis-1,2-dichloroethylene, chloroform, 1,1,1-trichloroethane, carbon tetrachloride, 1,2-dichloroethane, benzene, trichloroethylene, 1,2-dichloropropane, bromodichloromethane, cis-1,3-dichloropropene, toluene, trans-1,3-dichloropropene, 1,1,2-trichloroethane, tetrachloroethylene, dibromochloromethane, m-xylene, p-xylene, o-xylene, bromoform, and p-dichlorobenzene) was used for model samples. Adsorptive experiments were carried out by passing the air samples through a cartridge packed with HC-MWCNTs. Initial results showing high selectivity and high affinity for adsorbing aromatic VOCs (benzene, toluene, m-xylene, p-xylene, o-xylene, and p-dichlorobenzene) have provided new insight into the adsorption mechanisms. Data suggest that the HC-MWCNTs, unlike conventional carbon materials, adsorb aromatic compounds according to Fukui's frontier theory, which is based on the interactions between the HOMO and LUMO of the aromatic VOCs and those of the HC-MWCNTs.     

Colorimetric Artificial Nose for Identification of Breath Volatile Organic Compounds of Patients with Lung Cancer

A novel and highly sensitive colorimetric sensor array was developed for the detection and identification of breath volatile organic compounds（VOCs） of patients with lung cancer.Employing dimeric metalloporphyrins,metallosalphen complexes,and chemically responsive dyes as the sensing elements,the developed sensor array of artificial nose shows a unique pattern of colorific changes upon its exposure to eight less-reactive VOCs and their mixture gas at a concentration of 735 nmol/L within 3 min.Potential of quantitative analysis of VOCs samples was proved.A good linear relationship of 490-3675 nmol/L was obtained for benzene vapor with a detection limit of 49 nmol/L（S/N=3）.Data analysis was carried out by Hierarchical cluster analysis（HCA） and principal component analysis（PCA）.Each category of breath VOCs clusters together in the PCA score plot.No errors in classification by HCA were observed in 45 trials.Additionaly,the colorimetric sensor array showed good reproducibility under the cyclic sensing experiments.These results demonstrate that the developed colorimetric artificial nose system is an excellent sensing platform for the identification and quantitative analysis of breath VOCs of patients with lung cancer.     

基于气相离子迁移谱研究肺隐球病患者呼出气中特征挥发性有机物

该文采用气相色谱离子迁移谱(GC-IMS)对81例受试者呼出气样品进行了检测,包括临床确诊的20例肺隐球菌病患者,以及28例临床确诊的肺曲霉病患者和33例健康个体的对照样品,单个样品分析仅需10 min。结果显示,所有呼气样品中共检出19种挥发性有机物(VOCs)。通过主成分(PCA)分析发现,肺隐球病患者呼气中VOCs与健康对照组差异显著,但与肺曲霉病患者呼气中VOCs差异不显著。正交偏最小二乘判别模型(OPLS-DA)分析显示,与健康人群相比,肺隐球菌病患者呼气中特征VOCs为2-甲基-1-丙醛、异丙苯、2-戊酮、4-甲基-2-戊酮、丁醛和己醛;肺曲霉病患者的呼气特征VOCs为2-丁酮、2-戊酮、异丙苯、2-甲基-1-丙醛、4-甲基-2-戊酮和3-戊酮。此外,2种肺部感染患者呼气中特征性VOCs均包括2-甲基-1-丙醛、异丙苯、4-甲基-2-戊酮和2-戊酮,这表明丁醛和己醛在肺隐球菌病患者呼气中特异性略强,而2-丁酮和3-戊酮在肺曲霉病患者呼气中特异性更好。综上,采用GC-IMS可快速检出肺隐球病患者呼气中的VOCs,可用于后续数百例甚至数千例大样本分析,为更客观地评价呼气用于肺部真菌感染诊断的可行性提供必要的基础数据。     

Headspace solid-phase microextraction-gas chromatography-mass spectrometry applied to quality control in multilayer-packaging manufacture

A method based on headspace solid-phase microextraction-gas chromatography-mass spectrometry is proposed for the quality control of multilayer packaging and its manufacturing process. Volatile organic compounds (VOCs) are produced in the manufacturing process of the packaging. They can cause organoleptic problems or modify the properties of the packaging depending on the nature and the amount of the VOCs formed. The quantification using packaging samples with a known VOC concentration for the calibration is proposed in order to reduce the analysis time, and the method is validated using a statistical test. Finally, the method is applied to the determination of odour-responsible compounds in multilayer packaging samples obtained under different extrusion-coating conditions, i.e. type of extruder, type of polymer and extrusion speed.     

A new membrane inlet interface of a vacuum ultraviolet lamp ionization miniature mass spectrometer for on-line rapid measurement of volatile organic compounds in air

A novel membrane inlet interface coupled to a single-photon ionization (SPI) miniature time-of-flight mass spectrometer has been developed for on-line rapid measurement of volatile organic compounds (VOCs). The vacuum ultraviolet (VUV) light source for SPI was a commercial krypton discharge lamp with photon energy of 10.6 eV and photon flux of 10(10) photons/s. The experimental results showed that the sensitivity was 5 times as high as obtained with the traditional membrane inlet. The enrichment efficiency could be adjusted in the range of 10 to 20 times for different VOCs when a buffer cell was added to the inlet interface, and the memory effect was effectively eliminated. A detection limit as low as 25 parts-per-billion by volume (ppbv) for benzene has been achieved, with a linear dynamic range of three orders of magnitude. The rise times were 6 s, 10 s and 15 s for benzene, toluene and p-xylene, respectively, and the fall time was only 6 s for all of these compounds. The analytical capacity of this system was demonstrated by the on-line analysis of VOCs in single puff mainstream cigarette smoke, in which more than 50 compounds were detected in 2 s.     

Differentiation of isomeric compounds by two-stage proton transfer reaction time-of-flight mass spectrometry

We investigated a two-stage ion source for proton transfer reaction (PTR) ionization to achieve more selective mass spectrometric (MS) detection of selected volatile organic compounds (VOCs) than that achieved with commonly used PTR-MS instruments, which are based on single-step PTR ionization with H3O+. The two-stage PTR ion source generated reagent ions other than H3O+ by an initial PTR between H3O+ and a selected VOC, and then a second PTR ionization occurred only for VOCs with proton affinities larger than the affinity of the reagent VOC. Acetone and acetonitrile were useful as reagent VOCs because they provided dominant peaks as a protonated form. Using two-stage PTR-MS, we differentiated isomeric VOCs (for example, ethyl acetate and 1,4-dioxane) by means of differences in their proton affinities; protonated acetone formed the [M + H]+ ion from ethyl acetate but not from 1,4-dioxane. The PTR-MS-derived concentrations agreed quantitatively with those independently determined by Fourier transform infrared spectroscopy (FT-IR) at parts per million by volume (ppmv) levels. In addition, interfering fragment ions formed from alkyl benzenes at m/z 79 (C6H7+) could be distinguished from the m/z 79 ion arising from protonation of benzene, and therefore this method would prevent overestimation of benzene concentrations in air samples in which both benzene and alkyl benzenes are present. This two-stage PTR ionization may be useful for distinguishing various isomeric species, including aldehydes and ketones, if appropriate reagent ions are selected.