气相色谱分离多环芳香环境污染物用固定相的应用进展

综述了几种气相色谱固定相包括聚硅氧烷、液晶、冠醚、环糊精、离子液体及纤维填充固定相,在分离多环芳香烃(PAHs)、多环芳香化合物(PACs)及多氯联苯(PCBs)等环境污染物中的应用进展,展望了此类固定相的应用前景(引用文献64篇)。     

三检测通道-气相色谱法快速分析天然气的组成

采用配有五阀(2个十通阀和3个六通阀)、七柱(2根毛细管柱和5根填充柱)和三检测器(氢火焰离子化检测器A、热导检测器B和C)的气相色谱法测定了天然气的组分。借助阀的切换系统及设置的分析程序,一次进样便可实现天然气常规组分的测定。检测器A用于烃类气体的检测,检测器B用于永久气体的检测,检测器C用于氢气检测。根据标准样品组分的保留时间对未知样品作定性检测,用外标法进行定量测定。方法的精密度符合国家标准GB/T 13610-2003中的规定,本方法所测得的由标准气体所混合组成的标准样品中,各组分的测定值与标准值之间的相对误差均小于5%。     

热分析联用技术在高分子材料热性能研究中的应用

主要综述了热重-傅里叶变换红外(TG-FTIR)、裂解-色谱/质谱(Py-GC/MS)以及热重-质谱(TG-MS)三种常见的热分析联用技术的测试方法、原理,近几年这几种方法在高分子材料热性能研究中的应用进展和成果表明它们为材料的热分解过程和机理的探索提供了切实可行的研究方法,文章最后还展望了这些方法在热分析技术发展中的重要前景。     

15％哒螨灵乳油的气相色谱测定分析

采用气相色谱分析法,以实验室较常用AgilentDB -1毛细管色谱柱为分离柱,选择氢火焰离子化检测器,建立一种适合实验室开展哒螨灵质量分数检测的分析方法,经保留时间定性确证,峰面积外标法进行定量分析.结果表明,哒螨灵的线性相关系数为0.99913;变异系数为0.21％;平均回收率为98.38％.     

气相色谱法直接进样测定工业废气中的苯乙烯

建立了直接进样测定工业废气中苯乙烯的气相色谱法.工业废气样品通过气体进样阀进入气相色谱仪中进行分离和检测,采用0.25 mL气体进样阀时,方法的检出限为1.4 mg/m3,苯乙烯含量在3.19～51.0 mg/m3时,测定结果的相对标准偏差为2.19％～4.50％(n=5),与行业标准HJ 583-2010,HJ 584-2010相比,该方法操作简便、快速,适合工业废气中苯乙烯的快速测定.     

Fragmentation of oxime and silyl oxime ether odd‐electron positive ions by the McLafferty rearrangement: new insights on structural factors that promote α,β fragmentation

The McLafferty rearrangement is an extensively studied fragmentation reaction for the odd‐electron positive ions from a diverse range of functional groups and molecules. Here, we present experimental and theoretical results of 12 model compounds that were synthesized and investigated by GC‐TOF MS and density functional theory calculations. These compounds consisted of three main groups: carbonyls, oximes and silyl oxime ethers. In all electron ionization mass spectra, the fragment ions that could be attributed to the occurrence of a McLafferty rearrangement were observed. For t‐butyldimethylsilyl oxime ethers with oxygen in a β‐position, the McLafferty rearrangement was accompanied by loss of the t‐butyl radical. The various mass spectra showed that the McLafferty rearrangement is relatively enhanced compared with other primary fragmentation reactions by the following factors: oxime versus carbonyl, oxygen versus methylene at the β‐position and ketone versus aldehyde. Calculations predict that the stepwise mechanism is favored over the concerted mechanism for all but one compound. For carbonyl compounds, C–C bond breaking was the rate‐determining step. However, for both the oximes and t‐butyldimethylsilyl oxime ethers with oxygen at the β‐position, the hydrogen transfer step was rate limiting, whereas with a CH₂ group at the β‐position, the C–C bond breaking was again rate determining. n‐Propoxy‐acetaldehyde, bearing an oxygen atom at the β‐position, is the only case that was predicted to proceed through a concerted mechanism. The synthesized oximes exist as both the (E)‐ and (Z)‐isomers, and these were separable by GC. In the mass spectra of the two isomers, fragment ions that were generated by the McLafferty rearrangement were observed. Finally, fragment ions corresponding to the McLafferty reverse charge rearrangement were observed for all compounds at varying relative ion intensities compared with the conventional McLafferty rearrangement. Copyright © 2012 John Wiley & Sons, Ltd.     

全二维气相色谱-飞行时间质谱联用技术分析重馏分油中芳烃组成

通过对升温速度、二维补偿温度、调制周期等关键实验参数的优化,建立了全二维气相色谱-飞行时间质谱(GC×GC-TOF MS)分析重馏分油中芳烃组分的方法,得到了重馏分油芳烃组分按环数分布的二维点阵图。根据谱库检索、标准化合物对照及文献报道,对重馏分油芳烃组分中菲、甲基菲及芘、苯并蒽等常见多环芳烃(PAH)进行了准确定性,并将该方法应用到重馏分油加氢处理工艺研究中,对菲、芘的加氢处理产物进行了定性分析。该研究为重馏分油芳烃组分的准确定性提供了新的技术手段,为加深对油品加氢规律的认识提供了技术支持。全二维气相色谱与普通一维色谱对比,在重馏分油的芳烃组分分析上体现了极大优势。     

生物油储存稳定性实验研究

对松木和玉米芯快速热解制取的生物油进行储存稳定性实验,经过储存老化后的生物油黏度增大,水分含量和固体颗粒物含量增加,pH值、热值、密度无明显变化。通过GC-MS对储存前后生物油中主要组分进行定量分析表明,生物油经过储存后,羟基丙酮、乙酸、糠醛等主要组分的含量明显下降,而2-甲氧基苯酚、4-甲基-2-甲氧基-苯酚、4-甲基-苯酚的含量有所上升。核磁共振的碳谱分析表明,经过储存后生物油中甲氧基碳和双氧-烷基碳的含量降低,而芳基碳和不饱和碳的含量增大,生物油的芳香度有所提高。     

两种煤的次氯酸钠水溶液降解产物的分离与分析

两种煤于温和条件下在次氯酸钠水溶液中进行降解,所得水溶液经酸化后,水溶物依次用乙醚、CS2、石油醚、乙酸乙酯和苯进行分级萃取,萃取物经重氮甲烷酯化后用GC/MS分析。结果发现氯代物、脂肪酸和芳酸是煤的NaOCl水溶液降解的典型化合物,不同极性溶剂分级萃取可以实现产物的初步族组分分离。通过该研究建立煤的次氯酸钠氧化反应混合物有效分离和分析的方法,为煤的高附加值利用提供有效的途径。     

Quantification of paraquat in postmortem samples by gas chromatography-ion trap mass spectrometry and review of the literature

Paraquat (PQ) is an herbicide implicated in numerous fatalities, mainly caused by voluntary ingestion. Several methods have been used to quantify PQ in plasma and urine samples of intoxicated humans as a predictor of clinical outcome. There is no validated method for the analysis of PQ in postmortem samples. Therefore, the aim of this study was to develop an analytical method, using gas chromatography–ion trap mass spectrometry (GC‐IT/MS) after solid‐phase extraction, to quantify PQ in postmortem samples, namely in whole blood, urine, liver, lung and kidney, to cover the routes of distribution, accumulation and elimination of PQ. The method proved to be selective as there were no interferences of endogenous compounds with the same retention time as PQ and ethyl paraquat (internal standard). The regression analysis for PQ was linear in the range 0–10 µg/mL. The detection limits ranged from 0.0076 µg/mL for urine to 0.047 µg/mL for whole blood, and the recoveries were suitable for forensic analysis. The proposed GC‐IT/MS method provided an accurate and simple assay with adequate precision and recovery for the quantification of PQ in postmortem samples. The proof of applicability was performed in two fatal PQ intoxications. A review of the analytical methods for the determination of quaternary ammonium herbicides is also provided for a better understanding of the presently available techniques. Copyright © 2011 John Wiley & Sons, Ltd.