气体样品的动态预浓缩方法

 :通过迎头色谱常温吸附富集与反吹 峰切割 温度梯度热脱附技术的结合 ,建立了一套气体样品动态预浓缩装置 ,实现了室温条件下对沸点≥ - 10 3℃的气体样品的快速富集。该方法同时利用反吹切割带来的瞬间非稳定态和加热脱附时形成的温度梯度 ,实现了以较小的进样量得到较大的浓缩比的目的。用标准气体样品测试的结果是 :当进样量为 10mL时 ,浓缩倍数达到 10 0倍。     

兼具小气载吸附、快速换样和全面温控的程序升温脱附谱装置（英文）

程序升温脱附谱技术能定量识别表面物种和测量脱附动力学,因此被广泛应用于多相催化和表面科学研究.对于高效率和高质量的程序升温脱附谱实验而言,减小吸附过程中的气载并在不破坏超高真空条件下完成样品更换以及实现对样品全方位的温度控制是至关重要的.然而,现有的表面科学程序升温脱附谱装置通常无法同时满足这些条件.鉴于此,本文搭建了一台可实现小气载进样、快速换样以及全面温控的程序升温脱附谱装置.使用自动控制的基于微毛细管阵列的溢流分子束给样器,制备分子吸附的表面,让气体的进样更加精准并大幅减小了气载.借助液氮传输线并优化样品台处的热接触和热偶连接方式,使得这台程序升温脱附谱装置同时具备了快速换样、精准测温、快速降温以及稳定线性升温等功能.通过测量水从高定向热解石墨和TiO₂(110)表面的脱附特征以及甲氧基阴离子在TiO₂(110)表面的光催化氧化反应,证实了该程序升温脱附谱装置在测量脱附动力学参数、定量识别表面吸附物种和吸附位点以及分析表面光化学反应等方面的性能.本工作将为研究人员设计高效率和高质量的程序升温脱附谱装置提供宝贵的经验和思路.     

吸附浓缩/热脱附技术进展

热脱附技术较传统的溶剂洗脱法具有操作方便,富集浓缩效率高,不使用有机有毒溶剂等优点,是现代样品前处理的一项重要技术。作者着重介绍了用于热脱附吸附剂的选择及热脱附器的发展,并对９０年代以来浓缩富集／热脱附技术在不同领域中应用进展作一综述。     

水样品预处理仪器通过验收

大连物化所承担的科技部“九五”专题“毛细管固相微萃取器的研制与开发”,不久前通过验收。该仪器的研制成功,表明我国在水样品预处理和在线富集与色谱联用分析方面进入世界先进行列,是水质检测应用中关键技术的突破。 毛细管固相微萃取器采用毛细管柱内微萃取和热脱附方法相结合,实现了样品预处理—吸附—进样并与高分辨率气相色谱在线联用,解决了地表水、饮用水中痕量有机污染物的浓缩富集和样品预处理,富集倍数为103～104,用最普通的火焰离子化检测器检测,芳烃的最小检测限达2×10~(-10)(体积分数),满足水质分析的国际要求。该仪器操作简单,     

用于离子迁移率谱仪的快速热解析进样方法

热解析是用于离子迁移率谱仪(IMS)的液体和固体样品进样的重要手段,但在检测高沸点或易分解有机物时,存在易重新凝结或过热分解的问题.本研究建立了一种与IMS半透膜结合的热解析进样方法,设计了可快速加热的微型热解析装置,通过热子通电发热及热电偶测温实现对样品解析区域的升温控制,提高半透膜的进样效率.以低浓度三聚氰胺溶液为...     

吸附/热脱附气相色谱分析痕量C1～C5烃

本文以活性炭、TDX-01、Tenax GC、Porapak Q和GDX-104为吸附剂，不经冷凝，在常温下吸附富集痕量C1～C5烃并直接引入毛细管柱。同时探讨了吸附剂的最佳热脱附温度、饱和吸附量、吸附富集回收率、热脱附直接进样的线性规律及方法的相对偏差．     

流动注射—火焰原子吸收光度测定烧碱中铁

用氢氧化物沉淀法流动注射在线分离富集烧碱中铁，火焰原子吸收光度法测定，消除了大量基体的干扰，方法简便快速，而且对不同铁含量的样品，可改变进样量以保证富集后铁的合适浓度和足够的信号强度。本方法用于工业烧碱中铁的分析，平均加收率为９９．０％，变异系数为３．４％，检出限为１０５ｎｇ．ｍｌ＾－１。     

热脱附谱图的理论分析

热脱附技术已被广泛地用于研究金属丝、氧化物膜、氧化物催化剂和粉末样品的表面性质和脱附动力学.根据升温速度的不同,这一技术可分为两种:一种是在超高真空条件下使吸附物从快速加热的金属丝上脱附,称为闪光灯丝脱附(闪脱),闪脱技术对于清洁金属表面的气体吸附已提供了大量有价值的资料,但它仅能用于导热导电性能良好的金属材料;另一种是在真空体系或在惰性载气中,以较慢的加热速度使吸附物脱     

一种新的色谱在线预技浓缩分析白酒的方法

文中提出了一种新的在线预柱浓缩分析白酒的进样技术。采用Tenax—GC树脂为预柱中的吸附剂,应用了无阀切换和热脱附等技术。简便,快速是此法的主要优点;一次取样仅需样品10微升左右,一次操作周期约为一个小时。MES作为检测器,可不必求出组份的校正因子直接定量分析,并可给出各组份元素组成的数据。作者用此方法测定了五种白酒。此方法也可以用于其它饮料和类似稀水溶液样品的测定。     

一种新的色谱在线预柱浓缩分析白酒的方法

〕文中提出了一种新的在线预柱浓缩分析白酒的进样技术。采用Tenax-GC树脂为预柱中的吸附剂,应用了无阀切换和热脱附等技术。简便,快速是此法的主要优点;一次取样仅需样品10微升左右,一次操作周期约为一个小时。MES作为检测器,可不必求出组份的校正因子直接定量分析,并可给出各组份元素组成的数据。作者用此方法测定了五种白酒。此方法也可以用于其它饮料和类似稀水溶液样品的测定。     

烷基苯生产中循环烷烃的液固吸附色谱预分离和气相色谱/质谱分析

 利用 10 0目～ 2 0 0目的硅胶 ,选择正戊烷和二氯甲烷作为洗脱剂 ,采用吸附色谱法将烷基苯生产中的循环烷烃分离为饱和烃 (烷烃 +环烷烃 )及芳烃两部分。然后将饱和烃及芳烃分别进行色谱 /质谱 (GC/MS)联用分析 ,得到了有关循环烷烃构成的定性定量结果。定性结果如实地反映出烷基苯生产中的副反应产物 ,可直接用于指导生产。从定量结果可以看出 ,经过硅胶吸附分离后 ,试样中含量要求很低的芳烃被浓缩 ,提高了分析的准确度和灵敏度 ,可以检测出循环烷烃中含量很低的物质 ,为全面分析样品组成提供了有力的证据。     

Analysis of light hydrocarbons C1–C5 with Porous Layer Open Tubular fused silica columns of aluminum oxide. Part 1: The column

A method is described for the preparation of a Porous Layer Open Tubular (PLOT) fused silica column coated with submicron particles of aluminum oxide for the analysis of light hydrocarbons. The column is thermally stable and provides reproducible analytical data over a long period of time. The column can be operated at temperatures easily controlled by commercially available gas chromatographic apparatus. 1,3-Butadiene is retarded much more than its principal impurities: thus the polarity of aluminum oxide is extremely useful for butadiene analysis because none of the contaminants is obscured by the butadiene peak. The analysis of the 16 most common C₁–C₄ hydrocarbons is achieved within 5 min at 60°C with helium as the carrier gas. Conditioning of the carrier gas with water vapor from CuSO₄.5H₂O to decrease the activity of the aluminum oxide is described. Some applications of a 30 m × 0.32 mm aluminum oxide PLOT column are given.     

Comparing the weathering patterns of six oils using 3-way generalized Procrustes rotation and matrix-augmentation principal components

A case study is presented in which advanced chemical fingerprinting and data interpretation techniques are used to characterize and compare the weathering processes of six oil spillages made under controlled conditions (including the heavy oil released after the Prestige tanker sunk off the Galician coast-NW Spain on 2002). A tiered analytical approach using gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS) was applied along with two different approaches for 3-way analyses; namely, generalized Procrustes rotation, and matrix-augmented principal components analysis. Results showed that the two 3-way chemometric techniques leaded to essentially the same conclusions when analyzing three sets of compounds fingerprinting the spilled hydrocarbons (aliphatic hydrocarbons, polycyclic aromatic hydrocarbons (PAHs) and a set of diagnostic ratios). A steady evolution on the weathering of the oils was observed with both techniques, but for the diagnostic ratios. The variables involved on the weathering were the lightest aliphatic hydrocarbons and a general combination of the PAHs, which differentiated mostly among the light and the heavy products (fuel oils).     

High‐throughput gas chromatography for volatile compounds analysis by fast temperature programming and adsorption chromatography

The synergy of combining fast temperature programming capability and adsorption chromatography using fused silica based porous layer open tubular columns to achieve high throughput chromatography for the separation of volatile compounds is presented. A gas chromatograph with built‐in fast temperature programming capability and having a fast cool down rate was used as a platform. When these performance features were combined with the high degree of selectivity and strong retention characteristic of porous layer open tubular column technology, volatile compounds such as light hydrocarbons of up to C₇, primary alcohols, and mercaptans can be well separated and analyzed in a matter of minutes. This analytical approach substantially improves sample throughput by at least a factor of ten times when compared to published methodologies. In addition, the use of porous layer open tubular columns advantageously eliminates the need for costly and time‐consuming cryogenic gas chromatography required for the separation of highly volatile compounds by partition chromatography with wall coated open tubular column technology. Relative standard deviations of retention time for model compounds such as alkanes from methane to hexane were found to be less than 0.3% (n = 10) and less than 0.5% for area counts for the compounds tested at two levels of concentration by manual injection, namely, 10 and 1000 ppm v/v (n = 10). Difficult separations were accomplished in one single analysis in less than 2 min such as the characterization of 17 components in cracked gas containing alkanes, alkenes, dienes, branched hydrocarbons, and cyclic hydrocarbons.     

油页岩热解挥发分中轻油吸附回收工艺初探

将活性炭纤维吸附回收工艺应用于油页岩热解气轻质油品回收,自行建立了移动床油页岩连续热解实验装置及相应的油品回收系统。实验结果表明,冷凝冷却至室温的桦甸油页岩热解气中轻质油品含量可达20 g/m³以上。通过活性炭纤维吸附,可将煤气中的轻质油品完全回收。竞争吸附实验表明,"轻油"中的BTX、乙苯、C_10~13的烷烃、烯烃等更容易吸附,碳数相对较低的烯烃、烷烃、环烷烃吸附能力相对较弱。这将为油页岩热解气轻油高效回收工艺开发提供基础数据。     

Cu+ chemical ionization for analysis of hydrocarbons by gas chromatography/mass spectrometry

The use of copper ions for chemical ionization (CI) coupled with gas chromatography/mass spectrometry (GC/MS) of hydrocarbons is reported. Cu⁺?CI was performed in a high-pressure, fast atom bombardment ion source coupled with both a gas chromatograph and a mass spectrometer. The suitability of the Cu⁺?CI method is illustrated by the analysis of pure alkylbenzenes, alkylthiophenes, octenes, and by the analysis of a light mixture of aromatic hydrocarbons. The Cu⁺?CI/GC mass spectra display an abundant [M+⁶³Cu]⁺ ion, together with fragmentations, that are of structural interest. The detection limit for isobutylbenzene, taken as model compound, is 100 times lower than that for electron ionization.     

全二维气相色谱用于轻质石油馏分中芳烃含量的测定

建立了采用全二维气相色谱(GC×GC)技术一次进样完成轻质石油馏分中非芳烃、一环芳烃和二环芳烃的分离、定性 和定量。通过对柱系统的选择和色谱条件的优化,实现了一次全二维气相色谱分析即完成轻质石油馏分的族组成分离以及 目标化合物的分离。方法的加标回收率为89.5%～106.1%;样品中各组分含量重复测定的相对标准偏差均不大于5.8%,能 够满足样品测定的精密度和准确性要求,且完成1次分析最多只需要30 min。     

A new method to determine reid vapour pressure for stabilized crude oils by gas chromatography

Summary A new rapid method has been developed to determine Reid Vapour Pressure (RVP) for stabilized crude oils by gas chromatography. The quantity of light hydrocarbons dissolved in crude oil was measured directly by gas chromatographic analysis, while the RVP value was computed utilizing a new correlation with this quantity at constant temperature. A variety of crude oils were investigated and the results revealed the accuracy of this method.     

Coupling micro-LC and capillary GC as a powerful tool for the analysis of complex mixtures

A multidimensional chromatography system with a packed fused silica Micro-LC column connected on-line with capillary gas chromatography is presented. The Micro-LC column is used for group separation. Whole peaks are injected into the capillary GC column via an on-column injector. The reproducibility of the proposed transfer system for polyaromatic hydrocarbons is 3% to 7% relative standard deviation. The potential of this on-line Micro-LC-GC system is demonstrated by the analyses of PAH's and of a complex light gasoline fraction.     

Measurements of dissolved nonmethane hydrocarbons in sea water

Summary An automated stripping technique for the measurement of dissolved hydrocarbons in sea water is presented together with some results obtained during a ship cruise from Europe to Brazil. The sea water concentrations of NMHC were determined in a three step process: degassing, preconcentration, and gas chromatographic analysis. In a stripping chamber the dissolved gases were purged from sea water with helium. The stripped hydrocarbons were cryogenically concentrated, and after thermal desorption they were injected into the gas chromatograph. The light fraction (C₂–C₄) was separated on a packed and the heavy fraction (C₅–C₁₀) on a capillary column. All valves were microprocessor controlled in order to achieve an automated process. For the C₂–C₄ hydrocarbons the stripping efficiencies exceeded 90% except for acetylene (80%), the lower limit of detection was 1 to 4.5 pmol hydrocarbon per liter of sea water and the accuracy of the method was better than 25%, depending on the individual hydrocarbons. Typical oceanic concentrations were in the 10 and 100 pmol/l range. Alkenes were generally more abundant than the corresponding alkanes and within the homologous series the concentrations decreased with increasing number of carbon atoms.