顶空/气相色谱—质谱法测定固体废物中挥发性卤代烃的研究

建立了顶空,气相色谱-质谱法同时测定固体废物中35种挥发性卤代烃的方法,系统地研究了顶空条件对测定结果的影响,优化了色谱分离条件。结果表明,各挥发性卤代烃可以实现良好的分离;标准曲线相关系数均大于0．99,检出限为2-3μg/kg,不同浓度的相对标准偏差分别为5．3％～19％,1．8％-17％和4．2％-15％,样品加标回收率为70．8％-118％。该方法灵敏度高,具有良好的精密度和准确度,适用于固体废物中挥发性卤代烃的测定。     

气相色谱质谱法测定空气和废气中乙醇

建立了一种应用气相色谱-质谱法测定空气和废气中乙醇含量的分析方法;采用活性炭管吸附采样,异丙醇/二硫化碳混合解吸液解吸,经毛细管色谱柱分离,以气相色谱-质谱法测定乙醇的含量。该分析方法处理样品简便快速,无干扰,灵敏度高,检出限低,测定结果准确可靠,适用于环境空气和废气中乙醇的监测。     

激光实验中碘检测方法研究

建立了碱性活性炭管吸附-离子色谱法检测激光实验中碘方法。以0.5 L/min的流量采集15min激光实验工作场所空气中碘,采用碳酸氢钠-碳酸钠体系解吸活性炭上的碘离子,以碳酸氢钠-碳酸钠为淋洗液,Metrosep A Supp5(150mm)作为色谱分离柱,对离子色谱法分离和测定进行了研究。方法的相对标准偏差RSD在0.40%~0.89%,相关系数达到0.999 6,进样量为100μL时,方法的检出限达到0.004 mg/L。激光实验工作场所样品中碘测定的加标回收率为96.0%~102.5%。方法操作步骤简单,避免了各种衍生、萃取的过程,最大程度优化了激光实验中的碘采样方案,使得实验简便易行,结果准确可靠。     

污水处理厂挥发性含硫恶臭物质的测定

对污水处理厂的挥发性含硫恶臭物质进行低温分离和浓缩处理.应用气相色谱和气相色谱-质谱分析方法进行样品中各种无机硫化物、有机硫化物组的定性确认和定量测定。测定结果表明:被测定的样品中含有COS、H_2S、SO_2、CS_2、MM、Et-SH、DMS、DMDS等物质。此项监测可有效地控制、减少和消除恶臭污染。     

罐采样-GC/MS法测定环境空气中挥发性有机物

采用SUMMA罐采样,空气预浓缩与气相色谱/质谱联用技术,建立了39种常见挥发性有机物的分析方法。选取攀枝花市不同功能区的5个测点,采集了4个季度的环境空气样品220个,定性检出挥发性有机物54种,其中烃类占24%,卤代烃类占52%,含氧化合物占22%,其它化合物占2%。苯系物的检出率最高。定量的挥发性有机物最大浓度和平均浓度最高的项目均为苯,平均浓度4.59μg/m3,最大浓度29.8μg/m3。苯系物时间分布呈现出旱季高,雨季低的特点;日变化特征为早晨最高,整体呈下降趋势。     

热脱附-气相色谱质谱法测定环境空气中22种挥发性有机物

采用热脱附-气相色谱质谱联用仪建立环境空气中22种挥发性有机物的检测方法。通过吸附管吸附环境空气的挥发性有机物,再加热解析直接进入气质联用仪分析,外标法定量。结果表明,在5.00～100 ng曲线范围内,方法线性良好,所有目标化合物相关系数均大于0.995,采样体积为300mL时,方法检出限为0.002～0.005 mg/m~3。空白吸附管加标试验,回收率为90.3%～112%,6次平行试验测定结果 RSD为5.1%～14.4%。实验证明,该方法检出限低、精密度和准确度好,适用于环境空气中22种挥发性有机物的测定。     

大港油田地区挥发性有机物分析

采用热脱附气相色谱-质谱法对大港油田地区环境空气进行了监测分析,并对挥发性有机物(VOCs)的浓度变化趋势和组分进行了研究。结果表明:大港油田地区挥发性有机物的浓度水平冬季要高于其他季节,时间分布特征比较明显;其主要成分为硫化物、卤代烃和芳香烃三大类,为典型的石化类污染。在此基础上,结合油田实际情况,对减少挥发性有机物的污染提出了初步建议。     

基于GC-MS-FTIR的化学实验室挥发性有机物源强核算方法

文章针对化学实验室废气排放缺乏有效源强核算手段的现状,提出了一种基于气相色谱-质谱联用仪(GC-MS)和便携式傅立叶红外光谱分析仪(FTIR)联合监测的现场实测方法,并于2019年6月利用该方法对北京市某高校化学实验楼进行了12天的现场实测。研究结果显示,该高校化学实验楼的挥发性有机物(VOCs)排放量为1094.18±180.15kg/a,其中卤代烃、烷烃和含氧有机物占比较高,分别为57.5%、24.8%和21.0%。通过研究实验室试剂与废气的物质流关系,发现溶剂的使用是VOCs排放的重要来源,占全部来源的64.1%。对于高校化学实验室大气污染物排放的管控应该从源头和末端同时管理,通过严格管理实验室试剂的使用和增加末端尾气处理装置,从而降低实验室挥发性有机物的排放。     

水中10种挥发性有机物的快速检测

采用吹扫捕集与快速气相色谱-飞行时间质谱联用,建立测定水中10种石化行业常见挥发性有机物(VOCs)的吹扫捕集-快速气相色谱-飞行时间质谱的分析方法。通过质谱定性,选定目标物的特征离子,运用内标法定量,采用DN-624(20m×0.18mm×1μm)快速毛细管色谱柱,在10min内完成对水中10种VOCs的分析,在保证各目标物灵敏度和分辨率不受影响的同时,分析时间从标准方法的17min降至10min。该方法的线性、精密度与检出限满足标准方法 HJ 639—2012《水质挥发性有机物的测定吹扫捕集/气相色谱-质谱法》要求,通过实验验证,能够广泛应用于石化行业环境监测与应急监测。     

便携式ＧＣ-ＭＳ测定空气中有毒物质的应用

文章介绍了便携式气相色谱-质谱联用仪(Gas Chromatograph-Mass Spectrometer,GC-MS)的结构原理,结合应急监测的需要,说明了仪器性能参数与分析操作模式,探讨了标准曲线的建立与验证。通过仪器的实际应用,指出该仪器能够解决应急监测中目前存在的对有机污染物难以快速定性、定量的问题。利用捕集浓缩器富集待测定空气中挥发性有机化合物(VOCs),可迅速判断出气体样品中的挥发性有机化合物组分,给出定量测定结果。并根据日常使用情况,总结了便携式GC-MS性能特点。     

卤代烃作为降解抑制剂降低气相色谱/质谱分析方法中p,p’-DDT的降解

因为降低p,p’-DDT降解的传统方法会需要频繁清洁色谱系统及更换相关耗材,操作繁琐,耗时长,成本高,所以拟采用微量降解抑制剂减少和延缓p,p’-DDT分析时的降解率和降解频率。降解抑制剂为常见卤代烃类化合物,如四氯化碳等,降解抑制剂与样品同时进样分析。与传统方法比较,本方法不仅无需频繁清洁色谱系统及更换相关耗材,而且能显著降低p,p’-DDT降解率和降解频率,节约耗材及时间成本,操作简单快捷,不影响其它化合物的分析,回收率满足相关标准要求,为减少色谱分析中易降解化合物的降解提供了新的方法和思路。     

低温捕集/热解吸气相色谱法分析废气中挥发性硫化物

采用低温捕集/热解吸/火焰光度检测填充柱气相色谱法可分析废气中挥发性硫化物。标准气浓度为2.80g/L～38.10g/L时,硫化氢、甲硫醇、乙硫醇、甲硫醚和二甲二硫的平均回收率及相对标准偏差分别为92.1%～106.8%及0.5%～6.0%,采样体积为1.0L时,上述挥发性硫化物的最低检出浓度为0.08ng/L～0.65ng/L。该分析测定了炼油厂某些污染源和催化燃烧脱硫中试装置废气中挥发性硫化物组成,验证了方法的适用性。     

Attenuation of methane and volatile organic compounds in landfill soil covers

The potential for natural attenuation of volatile organic compounds (VOCs) in landfill covers was investigated in soil microcosms incubated with methane and air, simulating the gas composition in landfill soil covers. Soil was sampled at Skellingsted Landfill at a location emitting methane. In total, 26 VOCs were investigated, including chlorinated methanes, ethanes, ethenes, fluorinated hydrocarbons, and aromatic hydrocarbons. The soil showed a high capacity for methane oxidation resulting in very high oxidation rates of between 24 and 112 microg CH4 g(-1) h(-1). All lower chlorinated compounds were shown degradable, and the degradation occurred in parallel with the oxidation of methane. In general, the degradation rates of the chlorinated aliphatics were inversely related to the chlorine to carbon ratios. For example, in batch experiments with chlorinated ethylenes, the highest rates were observed for vinyl chloride (VC) and lowest rates for trichloroethylene (TCE), while tetrachloroethylene (PCE) was not degraded. Maximal oxidation rates for the halogenated aliphatic compounds varied between 0.03 and 1.7 microg g(-1) h(-1). Fully halogenated hydrocarbons (PCE, tetrachloromethane [TeCM], chlorofluorocarbon [CFC]-11, CFC-12, and CFC-113) were not degraded in the presence of methane and oxygen. Aromatic hydrocarbons were rapidly degraded giving high maximal oxidation rates (0.17-1.4 microg g(-1) h(-1)). The capacity for methane oxidation was related to the depth of oxygen penetration. The methane oxidizers were very active in oxidizing methane and the selected trace components down to a depth of 50 cm below the surface. Maximal oxidation activity occurred in a zone between 15 and 20 cm below the surface, as this depth allowed sufficient supply of both methane and oxygen. Mass balance calculations using the maximal oxidation rates obtained demonstrated that landfill soil covers have a significant potential for not only methane oxidation but also cometabolic degradation of selected volatile organics, thereby reducing emissions to the atmosphere.     

空气预浓缩气相色谱/质谱法测定南京环境空气中二硫化碳

采用不锈钢采样罐采集全量空气样品,使用空气预浓缩冷冻的方法从空气样品中提取二硫化碳,经气相色谱/质谱仪测定,判断确定空气恶臭物质的种类和污染来源。方法的最低检测浓度为0.003mg/m3,能够满足中国(TJ36-79)居住区大气中有害物质二硫化碳的最高容许浓度0.04mg/m3(一次值)标准的测定要求。     

Use of agricultural waste for the removal of nitrate-nitrogen from aqueous medium

The effectiveness of wheat straw charcoal (WSC) and mustard straw charcoal (MSC) as adsorbents for the removal of nitrate-nitrogen from water has been investigated. Commercial activated carbon (CAC) was used as a standard for comparison. The adsorption effectiveness of MSC was highest followed by CAC and WSC irrespective of the concentration of nitrate-nitrogen in the range of 0-25mg/l. The effects of temperature in the range of 15-28 degrees C on adsorption by WSC and MSC have also been investigated. It was observed that the temperature dependence of the adsorption effectiveness of MSC was higher than that of WSC and CAC. It is concluded that the MSC can be used for the in situ treatment by adsorption of nitrate-nitrogen in underground and surface water.     

Polycyclic aromatic hydrocarbons (PAHs) and estrogenic compounds in experimental flue gas streams

The importance of combustion processes as a source of substances with estrogenic activity in the environment was investigated. Wood (nontreated and treated with wood preservatives), barbecue charcoal, meat, and kitchen waste were combusted in a laboratory-scale incinerator. Flue gas emissions (particulates and gaseous pollutants) were trapped in polyurethane foam cartridges. The cartridges were subjected to Soxhlet extraction and part of the extracts redissolved in dimethylsulfoxide (DMSO) for analyses of estrogenic activity by means of the yeast-based human estrogen receptor (hER) bioassay. A synthetic estrogen, 17-alpha-ethinylestradiol (EE2), was used as the reference estrogenic compound. Part of the extracts was analyzed for the 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs). Estrogenic compounds in the flue gas (wood) were as high as 234 +/- 25 ng m(-3) EE2 equivalent compared with 27 to 81 ng m(-3) EE2 equivalent in flue gas from combustion of barbecue charcoal. Concentrations of polycyclic aromatic hydrocarbons in both flue gas streams were in the range of 21,000 +/- 2000 and 240 +/- 110 ng m(-3), respectively. In general, the concentrations of EE2 equivalent in the flue gas samples were at least a factor of 1000 lower than total PAH concentration. The EE2 levels were not related to the concentration of PAHs in any flue gas sample.     

紫外光度法测定水中挥发酚的研究

在国家标准方法中,测定挥发酚用4-氨基安替比林直接光度法和萃取光度法。但该方法测定范围小,上下限分别是2.5mg/L和0.12mg/L,且4-氨基安替比林、铁氰化钾等试剂不稳定,影响测定结果的准确度,方法繁琐。文章提出用紫外光度法测定水中的挥发酚。此方法不仅使测定范围增大到0.409～120mg/L,减少水样稀释比过大引起的误差及干扰,而且简便、快速、准确。通过实验证明,本方法与标准方法有很好的可比性及重现性。     

Non-conventional gas phase remediation of volatile halogenated compounds by dehydrated bacteria

Traditional biological removal processes are limited by the low solubility of halogenated compounds in aqueous media. A new technology appears very suitable for the remediation of these volatile organic compounds (VOCs). Solid/gas bio-catalysis applied in VOC remediation can transform halogenated compounds directly in the gas phase using dehydrated cells as a bio-catalyst.     

大口径毛细柱测定工作场所空气中的甲醇

采用大口径毛细柱气相色谱法测定工作场所空气中的甲醇,该方法利用硅胶管采集空气样品,超纯水解吸,DB-FFAP（30 m×0.53 mm×0.5μm）色谱柱,氢焰离子化检测器（FID）进行测定。方法的校正曲线相关系数r=0.999 94,线性范围20.30~203.0μg/ml,检出限1.9μg/ml,最低检出溶度1.3 mg/m3（以1.5 L样品计）,相对标准偏差为0.28%~0.53%,平均解吸率为96.3%,标准样品检查结果在参考范围内。实验结果表明,大口径毛细柱气相色谱法测定工作场所空气中的甲醇,方法精密度好,准确性和灵敏度高,适用于工作场所空气中甲醇的测定。