Sorptive Enrichment of Sulfur Compounds from Gaseous Samples on Polydimethylsiloxane

A method has been developed for preconcentrating the volatile sulfur compounds from gaseous samples using a trap filled with a sorption material, polydimethylsiloxane(PDMS), without the need for extensive cryotrapping with liquid cryogens. The system is based on enrichment of the solutes on a packed bed of 50% (w/w) PDMS on solid support without cryotrapping and is then analysed by using thermal desorption followed by capillary column (GS‐GASPRO) gas chromatography with simultaneous sulfur‐selective detection. The practicality of the system was demonstrated by the analysis of natural gas. Using the system described here, the sulfur gaseous compounds known to cause nuisance odors in the natural gas could be quantitatively trapped. The application of 50% PDMS on silcoport? for the analysis of sulfur compounds from gaseous samples has been proved to be useful.     

呼气中挥发性硫化物的质子转移反应质谱在线检测

利用自主研制的高灵敏呼气检测质子转移反应质谱(PTR-MS),对一名口臭受试者的口腔吹出气体、鼻子呼出气体和口腔内气体分别进行多组分实时监测,发现了该受试者呼气中3种引起口臭的挥发性硫化物(VSCs)的来源并不相同,其中甲硫醇主要来源于口腔,硫化氢和二甲基硫则主要来源于肺或呼吸道.本研究不仅发现了口腔内气体在PTR-MS呼气监测过程中的特征变化趋势,还分析了呼出气体中3种VSCs的来源,对于呼气的正确采样和检测具有重要的指导意义.     

Correlation between Electron Capture Response and Chemical Structure for Sulfur Compounds

Abstract

The temperature dependence of the electron capture process was investigated for a series of divalent sulfur compounds. The electron affinity and/or the activation energy for the electron capture reaction were calculated for individual compounds by plotting In KT^3/2 vs. 1/T, where K is the electron capture coefficient and T is the absolute temperature in the detector. The correlation between these values and chemical structure was discussed by means of 3d orbital resonance of the sulfur atom.     

Analysis of Total Non-Volatile Non-Sulfide Reduced Sulfur in Potable and Untreated Surface and Groundwaters

Abstract

An analytical method was developed to measure the total concentration of non-volatile non-sulfide reduced sulfur in treated and untreated surface and groundwater. The method was based on the alkaline reduction by Raney nickel (prepared in situ from Raney alloy) of organic and inorganic sulfur compounds (in oxidation states below +6) to sulfide. Sulfide was swept out of the reflux apparatus under nitrogen into a trap of zinc acetate and determined colorimetrically as ethylene blue. The recoveries obtained from solutions of elemental sulfur, sulfide, sulfite, thiosulfate, tetrathionate, cysteine, cystine, methionine, glutathione, allylthiourea, sulfanilamide and thiocyanate ranged from 84–102% with typical recoveries of approximately 90%. Sulfate was not detectable by the procedure. Chlorine present in potable water samples interfered in the procedure and was removed with sodium borohydride. The relative standard deviation of the method varied from 0.25 to 5.6% and averaged 3%. The detection limit based on a 500 mL sample was 3 mg m^?3.     

催化裂化汽油中硫化物的气相色谱-原子发射光谱分析方法及应用

采用气相色谱-原子发射光谱联用(GC-AED)技术,建立了催化裂化汽油中各种硫化物类型分布的分析方法。考察了色谱条件对催化汽油中各种硫化物分离的影响,定性了催化汽油中的60余种硫化物,首次计算了程序升温条件下汽油馏分中各种硫化物的保留指数,为不同实验室的定性比较提供了依据。该方法可应用于不同来源汽油中各种硫化物类型分布的研究。     

利用大口径毛细管气相色谱法测定液化气中的含硫化合物

利用大口径毛细管色谱柱、不分流进样、氢焰离子化检测器（ＦＩＤ）、双火焰光度检测器（ＤＦＰＤ）,与气相色谱－质谱（ＧＣ－ＭＳ）联用技术相结合,对脱硫后的液化气进行测定,成功地鉴定出１７种含硫化合物。该法简便、快速,对含硫化合物的检测灵敏度高。     

气相色谱法测定催化柴油中硫化物类型分布及数据对比

采用气相色谱-氢火焰离子化检测器-硫化学发光检测器（GC—FID—SCD）联用技术,建立了催化柴油中各种硫化物类型分布的分析方法。考察了色谱条件对催化柴油中各种硫化物分离的影响,定性了某催化柴油中的120多个硫化物,该方法还可以同时提供催化柴油中正构烷烃含量的分布信息。硫化物中的硫在1．5—700mg／L时其峰面积与质量浓度呈较好的线性关系,相关系数达0．9999,响应与硫化物的类型无关。催化柴油中苯并噻吩、4-甲基苯并噻吩、二苯并噻吩、4-甲基二苯并噻吩和4,6-二甲基二苯并噻吩等主要硫化物浓度测定的相对标准偏差（RSD）均小于5．0％。当信噪比（S／N）为3时,测得苯并噻吩硫的检出限为0．1mg／L。将该方法用于不同来源柴油中各种硫化物类型分布的研究,并与气相色谱一原子发射光谱检测器（GC—AED）测硫的数据进行了对比,两种检测器的定量结果大多数具有较好的相关性,相关系数大于0．95。     

Determination of Sulfur Compounds in Air by Chemiluminescence

Abstract

The present review is devoted to applications of chemiluminescence to the analysis of trace sulfur species in air. Determinations of oxidized (sulfur dioxide and sulfite), reduced (hydrogen sulfide, dimethyl sulfide, carbonyl sulfide, carbon disulfide and mercaptans) and/or sulfur compounds in general are described and some practical considerations are discussed. The development of detectors based on chemiluminescence in the aproximately last fifteen years is also reviewed.     

High Pressure Liquid Chromatography of Selected Sulfur Compounds

Abstract

High pressure liquid chromatography was used to separate and determine quantitatively the following groups of sulfur compounds: thiols, sulfides, disulfides, sulfones, isothiocyanates, thioamides, and thioureas. Amperometric and UV detectors were compared; for thiols, thioureas, isothiocyanates, and thioamides, the former was generally more sensitive. With the exception of alkyl and cycloalkyl sulfides, the liquid chromatographic method can be used for the analysis of the investigated sulfur compounds below the ppm range. The method developed was compared to gas chromatography with flame photometric detection. The latter was found to be superior for the analysis of alkyl and cycloalkyl thiols, sulfides and disulfides of molecular weight below 200, whereas the former was more suitable for the analysis of aromatic thiols, sulfides and disulfides, as well as thioamides, isothiocyanates, and thioureas. Both methods were equivalent for the analysis of aromatic sulfones.     

紫外荧光光谱法测定焦炉气中的痕量总硫

采用紫外荧光光谱法测定焦炉气制取液化天然气的原料气中痕量总硫,考察了样品引入速率、进样量、气体流量、燃烧温度、取样方式和进样方式等条件对分析结果的影响。总硫检出限为15μL·m-3,测定结果与气相色谱法和微库仑法的结果相吻合,测定值的相对标准偏差(n=7)小于10%。     

电感耦合等离子体原子发射光谱法测定玻璃中总硫

应用电感耦合等离子体原子发射光谱法(ICP-AES)测定了玻璃中总硫量。对测定条件,包括试样的溶解方法,分析谱线的选择,共存元素的光谱干扰及仪器的工作参数等作了系统研究。测定中选择了在紫外区的谱线(S 181.972 nm)作分析线可有效地避免了基体中大量钙的干扰。选取5件标准样品或已知样品按所提出方法各进行5次分析,算得方法的RSD值均小于1.5%,进行11次空白试验,算得方法的检出限(3S)为0.01 mg.L-1。通过对两件标准参考物质(NBS 89和GBW 03117)及一件已知样品的分析,验证了方法的准确度,所得测定结果与证书值或已知值相符。     

顶空气相色谱法测定杏脯中二氧化硫

建立顶空气相色谱测定杏脯中二氧化硫残留的方法,探讨了气液体积比、加酸量、平衡温度和平衡时间对检测结果的影响。向450 mL顶空瓶内加入5 g样品、10 g石蜡、200 mL水及25 mL盐酸溶液,于75℃平衡20 min后放至室温,抽取0.5 mL顶空气体进行定性定量分析检测。该方法标准工作曲线线性相关系数r~2为0.992,检出限和定量限分别为0.1,1.0 mg/kg,测定结果的相对标准偏差为1.9%~3.2%(n=6),样品加标回收率为89.4%~94.3%。该法操作简便、快捷,灵敏度高,人为误差小,满足杏脯中二氧化硫残留的批量检测要求。     

Rate Constants for Reactions of •OH with Several Reduced Sulfur Compounds Determined by Relative Rate Constant Method

The rate constants for the reactions between •OH and six reduced sulfur compounds in air, N₂, and O₂ were measured using relative rate constant method in a 180-L Teflon bag at 298 K and 1.013×10⁵ Pa. These results were compared with previous published data and were discussed in terms of trends in different buffer gases.     

吸收液采样-顶空-气相色谱法测定废气中吡啶

用吸收液采集废气样品,顶空进样,采用气相色谱法测定进样气体中吡啶的含量。用DB-FFAP毛细管色谱柱分离,氢火焰离子化检测器测定。优化的试验条件如下:①采用多孔玻板吸收瓶采集样品;②吸收液的体积为45mL;③采样流量为0.5L·min^-1;④样品在4℃下,7d内完成分析;⑤吸收液的pH大于12;⑥加入3g氯化钠调节吸收液离子强度;⑦顶空温度为80℃,顶空平衡时间为30min。吡啶的质量浓度在100mg·L^-1以内与其对应的峰面积呈线性关系,检出限为0.05 mg·m^-3。对3个不同浓度水平的吡啶标准气体进行测定,相对误差为-8.0%^-4.7%,测定值的相对标准偏差(n=6)为1.3%~7.8%。     

俄罗斯直馏柴油中硫化物的分离富集与结构鉴定

采用选择性氧化剂和还原剂对俄罗斯直馏柴油中的硫醚类硫化物和噻吩类硫化物分别进行分离和富集,得到两者的浓缩液。运用质谱技术对分离出的硫化物结构进行鉴定。结果表明:氧化还原法是分离俄罗斯直馏柴油中硫化物的有效方法;硫醚类硫化物浓缩液中鉴定有烷基四氢噻吩和烷基四氢噻喃类化合物,四氢噻喃类硫化合物的烷基取代碳数在C4~C13范围;噻吩类硫化物浓缩液中有烷基侧链长度为C0~C9之间的苯并噻吩,烷基侧链长度为C0~C3之间的二苯并噻吩。     

海水和大气中挥发性硫化物分析方法的研究

建立了大气和海水中挥发性硫化物的气相色谱分析方法,确定了最佳实验条件.为了适应不同的基质和保存方式,大气和海水样品采用了不同的分析方法.测定大气样品时,采用大气采样罐及三级冷阱预浓缩气相色谱-质谱联用技术,而海水样品采用吹扫捕集-气相色谱测定.本方法测定大气挥发性硫化物的线性范围较好,精密度为7.7%~15.1%,检出限为0.23~4.7 ng;海水中挥发性硫化物的精密度为3.5%~5.3%,检出限为2.5~3.5 ng.将本方法用于青岛近海海水和大气中硫化物的测定,测得海水中羰基硫、二甲基硫和二硫化碳的平均浓度分别为(268±58)pmol/L、(1264±0.2)pmol/L、(19±2)pmol/L,大气中的平均浓度为543±39、39±9和56±20(×10-12,V/V).本方法可准确测定海洋环境中的挥发性硫化物.     

A Low Cost Gas Sampling Valve and Gc Set-Up for Analysis of Low Concentration Gas Mixtures

Abstract

A gas sampling valve suitable for on-line injection of low pressure (< 0.5 torr) gas mixtures is described. Its advantages over the commercially available valves are enumerated. An error of < 3 per cent due to non-reproducibility in sample injection was observed. A simple arrangement of column and hot wire detector together with this valve enabled quantitative separation of CO and O₂ with a lower limit of ～ 1 × 10^?7 moles for each component.     

挥发性有机物在3种采样装置中的稳定性

详细研究了50种挥发性有机物在Summa采样罐、Teldar采样袋和铝箔采样袋中的稳定性。Summa采样罐适合采集所有50种有机化合物；Teldar采样袋适合采集沸点低于150℃的有机物；铝箔采样袋适合采集沸点低于60℃的有机物。3种采样装置对有机物的吸附能力与有机物的沸点呈线性负相关。铝箔采样袋的吸附方程斜率的绝对值最大；其次是Teldar采样袋；最少是Summa采样罐。     

Artifacts Observed When Using Tenax-GC for Gas Sampling

Abstract

Artifact peaks have been observed when samples of the detonation products of a number of U.S. Navy explosives were collected on Tenax-GC, desorbed with pentane, and analyzed by gas chromatography/mass spectrometry (GC/MS). We have shown that the formation of these spurious peaks takes place slowly when Tenax-GC is stored in the dark, but the formation is greatly accelerated when air flows over this polymeric absorbent.     

气相色谱法测定硫化橡胶中微量游离硫的含量

测定硫化橡胶中游离硫含量常用的方法有化学滴定法、薄层显色法和紫外光谱法。这些方法操作繁琐,并且只适用于常量分析。薄层显色法所用的显色剂叠氮化钠是剧毒和易爆炸的药品,实验条件比较苛刻。本文采用GC-ECD法测定了15个硫化橡胶中游离硫的含量,与化学方法进行了对照,二者结果相符。与以前所用的方法相比,本方法样品和溶剂用量少,提取时间短,灵敏度和精度高,是测定硫化橡胶中微量游离硫的简便、快速方法,尚未见报道。