低价钛盐还原反应的研究——Ⅲ.2,2-二芳基-1,l,l-三氯乙烷与低价钛盐的反应

2,2-二芳基-1,1,1-三氯乙烷(1)与TiCl_4-Zn起脱氯还原重排反应生成1,2-二芳基乙烯(3)。与TiCl_4-Mg反应时,2,2-二(对甲苯基)-1,1,1-三氯乙烷和2,2-二(对乙氧苯基)-1,1,1-三氯乙烷(1c,1d)主要得到重排产物2,2-二芳基乙烯(3)和2,2-二芳基-1-氯乙烯(4),后者可能是由相应的2,2-二芳基-1,1-二氯乙烷(2)生成的。但2,2-二苯-1,1,1-三氯乙烷和2,2-二(对氯苯基)-1,1,1-三氯乙烷(1a,1b)与此试剂反应只生成还原产物2,2-二芳基-1,1-二氯乙烷(2a,2b)。     

低价钛盐还原反应的研究——Ⅲ.2,2-二芳基-1,1,1-三氯乙烷与低价钛盐的反应

2,2-二芳基-1,1,1-三氯乙烷(1)与TiCl₄-Zn起脱氯还原重排反应生成1,2-二芳基乙烯(3)。与TiCl₄-Mg反应时,2,2-二(对甲苯基)-1,1,1-三氯乙烷和2,2-二(对乙氧苯基)-1,1,1-三氯乙烷(1c,1d)主要得到重排产物2,2-二芳基乙烯(3)和2,2-二芳基-1-氯乙烯(4),后者可能是由相应的2,2-二芳基-1,1-二氯乙烷(2)生成的。但2,2-二苯-1,1,1-三氯乙烷和2,2-二(对氯苯基)-1,1,1-三氯乙烷(1a,1b)与此试剂反应只生成还原产物2,2-二芳基-1,1-二氯乙烷(2a,2b)。     

平衡均匀水平试验确定挥发性有机化合物测量方法的精密度

挥发性有机化合物通常使用吹扫捕集色谱法检测。在7家协作实验室进行平衡均匀水平试验,测定了水中氯乙烯、1,1-二氯乙烯、二氯甲烷、反-1,2-二氯乙烯、1,1-二氯乙烷、氯仿、1,1,1-三氯乙烷等24种挥发性有机化合物。测量结果经一致性和离群值检验后,计算得重复性标准差范围为0.085～5.350μg/L,再现性标准差范围为0.096～7.737μg/L。对标准差和平均值拟合函数关系,得到精密度最终值。     

氮气中六种氯代烷烃混合标准气体的研制

介绍了氮气中6种氯代烷烃混合标准气体的制备和定值方法。标准气体的组分是二氯甲烷、三氯甲烷、1,1-二氯乙烷、1,2-二氯乙烷、1,1,1-三氯乙烷和1,1,2-三氯乙烷,标准值为5 μmol/mol。考察了标准气体的制备重现性、均匀性和稳定性。结果表明,标准气体在气瓶内均匀性良好,扩展相对不确定度为5%,使用有效期为一年。经与国外的同类标准气体比对,量值有较好的一致性。氮气中6种氯代烷烃混合标准气体的研制为挥发性氯代烷烃的检测提供了计量标准。     

饮用水中可吹脱的有机卤代烃的测定

在生活饮用水的工艺处理过程中,通常需要进行加氯消毒,因此会产生一些有机卤代烃,如1,1,1-三氯乙烷、1,1,2-三氯乙烷、三溴甲烷、1,2-二氯乙烷、1,1,2,2-四氯乙烷、1,1-二氯乙烯、三氯乙烯、四氯乙烯等挥发性有机物.如何对这些挥发性有机物进行快速准确测定对保护人体健康有着重要意义.本方法采用气提-捕集方法和气相色谱-质谱联机技术,定性定量检测饮用水及水源水中的VOCs含量.     

毛细管柱气相色谱法测定修正液中有害物质

应用带有电子捕获检测器的毛细管柱气相色谱法分析了修正液中的有害组分,用对测定无干扰的溶剂n-庚烷稀释修正液样品并测定了其中的5种对人体有害的氯代烃,即二氯甲烷、三氯甲烷、四氯化碳、1,1-二氯乙烷及1,1,1-三氯乙烷.方法的检出限(3S/N)在0.001～10.0 mg·kg-1范围内,相对标准偏差(n=6)在2.45%～3.01%之间,标准加入回收率在97.6%～104.0%之间.     

静态顶空/气相色谱-质谱法同时测定化妆品中22种有毒挥发性有机溶剂残留

以2015版《化妆品安全技术规范》中规定的常见禁用及限用有毒挥发性有机溶剂为研究对象,建立了静态顶空/气相色谱-质谱法(SHS/GC-MS)同时测定化妆品中22种有毒挥发性有机溶剂(VOC)(二氯甲烷、顺式-1,2-二氯乙烯、反式-1,2-二氯乙烯、2-氯-1,3-丁二烯、三氯甲烷、1,2-二氯乙烷、苯、四氯化碳、三氯乙烯、甲苯、四氯乙烯、氯苯、乙苯、三溴甲烷、间二甲苯、对二甲苯、苯乙烯、邻二甲苯、异丙苯、1,4-二氯苯、1,2-二氯苯、六氯丁二烯)残留的检测方法。试样在80℃下30 min静态顶空,经DB-1柱分离后,采用选择离子监测模式(SIM)进行定性定量分析。优化了顶空、色谱和质谱参数,结果表明:22种VOC在0.5~50 ng/m L浓度范围内均呈良好的线性关系,相关系数均大于0.99,在1.0,2.0,5.0 ng/m L 3个浓度加标水平下的平均回收率为80.3%~102.7%,相对标准偏差(RSD,n=6)为6.4%~9.9%,检出限为0.2~5.0 ng/g。结果表明,该方法简便、灵敏、准确,具有良好的重现性和稳定性,适合于化妆品中22种VOC残留的筛查和确证检测。     

顶空-气相色谱/质谱法测定溶剂型木器涂料中7种卤代烃

建立了顶空-气相色谱/质谱(HS-GC/MS)法测定溶剂型木器涂料中卤代烃含量的方法。采用HS-GC/MS测定了二氯甲烷、1,1-二氯乙烷、三氯甲烷、1,1,1-三氯乙烷、四氯化碳、1,2-二氯乙烷、1,1,2-三氯乙烷7种化合物,样品经丙酮稀释,外标法定量。结果表明:7种卤代烃含量在0.05~500 mg/L范围内线性关系良好,相关系数(r2)大于0.994,定量限为0.05~0.2 mg/kg。加标回收率64.4%~107.7%,相对标准偏差为4.1%~11%(n=6)。方法已用于溶剂型木器涂料中卤代烃的定性、定量分析。     

气质联用法分析化妆品中的苯、二硫化碳和氯代烃

苯、二硫化碳、二氯甲烷、氯仿、四氯化碳、1,2 二氯乙烷、1,1,1 三氯乙烷、六氯乙烷、四氯乙烯等有机化合物对人体均有一定的毒性。目前仅有用气相色谱法分析化妆品中苯、二氯甲烷和1,1,1 三氯乙烷的文献报道[1,2],其他6种化合物的相应分析方法尚未见报道。本文采用气相色谱 质谱联用技术对同时分析含抛射剂类化妆品中的这9种化合物作了初步研究。1　实验部分1.1　主要仪器和条件　　ＨＰ6890ＧＣ/5973ＭＳ气质联用仪,ＨＰ ＶＯＣ中极性毛细管色谱柱(30ｍ×0 2ｍｍｉ ｄ ×1 1μｍ)。　　气相色谱仪进样口气化温度200℃;载气(Ｈｅ)流量…     

冠醚化合物的合成(ⅩⅠⅩ)——双羟基冠醚衍生物的合成

本文用3,5-二叔丁基二苯并-14-冠-4双羟基冠醚的顺式和反式异构体分别与溴乙酸、3-溴丙酸及氯代乙酰氯反应,制备了4个双羧酸冠醚及2个双氯代乙酸酯冠醚衍生物。此外,通过1,1′-(邻苯)-双-(2,3-环氧丙基)醚与2,2′-联苯二酚反应,合成了联苯型苯并14-冠-4双羟基冠醚,分离了顺、反异构体,并使之与溴乙酸反应,制备了相应的双羧酸冠醚衍生物。10个新化合物的结构均经IR、¹H NMR、MS和元素分析确定。     

Thermal desorption—gas chromatography for the determination of benzene, aniline, nitrobenzene and chlorobenzene in workplace air

Sampling on Tenax TA of different mesh sizes followed by thermal desorption and gas chromatography was evaluated as a simple method for the determination of benzene, aniline, nitrobenzene and chlorobenzene in the workplace air. An alternative sampling technique in place of pump sampling was developed. Quantitative recoveries were obtained in the mass range 0.04–10 μg. It was found that air humidity had no effect on recovery. The charged tubes can be stored at room temperature for 5 days with no change in recovery. The particle size of Tenax TA has no significant effect on adsorption and desorption.     

Determination of volatile organic hydrocarbons in water samples by solid-phase dynamic extraction

In the present study a headspace solid-phase dynamic extraction method coupled to gas chromatography–mass spectrometry (HS-SPDE-GC/MS) for the trace determination of volatile halogenated hydrocarbons and benzene from groundwater samples was developed and evaluated. As target compounds, benzene as well as 11 chlorinated and brominated hydrocarbons (vinyl chloride, dichloromethane, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, carbon tetrachloride, chloroform, trichloroethylene, tetrachloroethylene, bromoform) of environmental and toxicological concern were included in this study. The analytes were extracted using a SPDE needle device, coated with a poly(dimethylsiloxane) with 10% embedded activated carbon phase (50-μm film thickness and 56-mm film length) and were analyzed by GC/MS in full-scan mode. Parameters that affect the extraction yield such as extraction and desorption temperature, salting-out, extraction and desorption flow rate, extraction volume and desorption volume, the number of extraction cycles, and the pre-desorption time have been evaluated and optimized. The linearity of the HS-SPDE-GC/MS method was established over several orders of magnitude. Method detection limits (MDLs) for the compounds investigated ranged between 12 ng/L for cis-dichloroethylene and trans-dichloroethylene and 870 ng/L for vinyl chloride. The method was thoroughly validated, and the precision at two concentration levels (0.1 mg/L and a concentration 5 times above the MDL) was between 3.1 and 16% for the analytes investigated. SPDE provides high sensitivity, short sample preparation and extraction times and a high sample throughput because of full automation. Finally, the applicability to real environmental samples is shown exemplarily for various groundwater samples from a former waste-oil recycling facility. Groundwater from the site showed a complex contamination with chlorinated volatile organic compounds and aromatic hydrocarbons. Figure SPDE Principle     

Thermal desorption-capillary gas chromatography for the quantitative analysis of dimethyl sulphate, diethyl sulphate and ethylene oxide in the workplace

Sampling on solid adsorbents followed by thermal desorption and gas chromatography was evaluated as a simple method for the quantitative analysis of dimethyl sulphate, diethyl sulphate and ethylene oxide in the workplace environment. Tenax TA and Carbosieve S-III (for ethylene oxide) were found to be suitable adsorbents. The charged tubes can be stored at 22 degrees C for 4 days. The recovery is better than 98% (greater than 80% for ethylene oxide) in the mass range 1 ng-1 micrograms. The recovery is not dependent on air humidity. The limits of detection tested were at the lower parts per billion level.     

气相色谱法测定工作场所空气中的毒死蜱

建立气相色谱测定工作场所空气中毒死蜱的方法。采用硅胶管采集空气样品,丙酮溶剂解吸,用气相色谱工作曲线法测定毒死蜱的含量。在采样体积为4.5 L,解吸体积为1.0 m L的条件下,空气中毒死蜱的含量在0.022~2.2μg/L范围内与色谱峰面积呈良好的线性关系,线性相关系数为0.999 5,检出限为0.002μg/L。加标回收率为99.4%~97.3%,测定结果的相对标准偏差为4.6%~6.0%(n=6)。该方法适合测定工作场所空气中的毒死蜱。     

一次热解吸直接进样浓缩方法的研究--室内大气中挥发性有机化合物的分析

研制了新型的一次热解吸直接进样热解析仪．考察了新型热解吸仪热解吸定量的重复性、准确性、热解析率、线性等性能．通过实际采样分析证明,该方法提高了浓缩倍数,操作简单,易于掌握,定量重复性好、准确度高,分析结果可靠．适合大批量样品的分析测试．     

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.     

活性氧化铝柱-气相色谱法测定工作场所空气中“四烯”的方法研究

采用活性氧化铝柱-气相色谱法对作业场所空气中乙烯、丙烯、丁烯、丁二烯进行活性炭采样,热解吸后进样分析。活性炭管对"四烯"的吸附性良好,测定结果的相对标准偏差为0.37%～2.08%;乙烯、丙烯、丁烯、丁二烯检出限分别为0.0010、0.000520、.00083、0.0003 mg/L;样品的平均解吸效率为93.7%～98.59%;样品的平均采样效率为93.9%～99.1%;乙烯、丙烯、丁烯、丁二烯穿透容量分别为9.58、.87、.4、7.1 mg;样品在室温下放置7 d,其平均样品损失率不大于5.58%,在4～10℃环境放置10 d,其平均样品损失率不大于7.11%,空气中乙烷对本方法无干扰。该法可满足职业卫生检测的要求。     

气相色谱–质谱法测定工作场所空气中的5种卤代烃

建立二硫化碳解吸气相色谱–质谱法同时测定工作场所空气中5种卤代烃快速灵敏的分析方法。采用活性炭管采集空气样品,以二硫化碳解吸,应用DB–624色谱柱分离及气相色谱–质谱联用的方法对工作场所空气中的三氯甲烷、四氯化碳、二氯乙烷、三氯乙烯、四氯乙烯5种卤代烃进行同时定性及定量分析。在所选定的条件下,5种卤代烃可实现基线分离,标准工作曲线线性良好,相关系数r≥0.998,加标回收率在93.9%~102.0%之间,测定结果的相对标准偏差小于5%(n=6)。该方法简单、快速,选择性好,灵敏度高,重现性好。     

Detection of the chemical warfare agents bis-(2-chloroethyl)ethylamine (HN-1) and tris-(2-chloroethyl)amine (HN-3) in air.

This paper describes the method development and validation for detection of the chemical warfare agents HN-1 and HN-3 in air using C8 solid-phase extraction disks followed by liquid desorption and analysis by gas chromatography. The method is contrasted to the standard approach which uses solid sorbent tubes followed by thermal desorption and analysis by gas chromatography.     

Automated high-speed analysis of selected organic compounds in urban air by on-line isotopic dilution cryofocusing gas chromatography/mass spectrometry

An automated environmental air monitor has been developed to measure selected organic compounds in urban air. The instrument is based on a cryofocusing-thermal desorption gas chromatographic mass spectrometry technique where the mass spectrometer is a slightly modified residual gas analyzer (RGA). The RGA was chosen as a detector because the whole system must be robust for long periods, with 24-h continuous air monitoring. RCA are extremely simple and seemed the most reliable mass spectrometers for this purpose. Moreover, because they have no physically limited ion source, contamination is considerably reduced, so maintenance intervals are longer. The gas chromatograph is equipped with a computer-controlled six-way sampling valve, with a 100-mL sampling loop and thermal desorption cold trap injector. Environmental air is enriched with an isotopically labeled internal standard in the sampling line. This internal standard is added with a validated, custom-made, permeation tube device. The “on-line” internal standard provides for high quality quantitative data because all variations in instrument sensitivity in cryofocusing or in thermal desorption efficiency are taken into account. High repetition rates (down to 5 min for a full analytical cycle) are obtained with the use of an isothermal gas chromatography program, microbore capillary column, and environmental air sampling during the gas chromatography run.