共查询到19条相似文献,搜索用时 46 毫秒
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固相微萃取-气相色谱/同位素质谱法测定水中挥发性有机物单体碳同位素 总被引:1,自引:0,他引:1
建立了采用75μm碳分子筛/聚二甲基硅氧烷(CAR-PDMS)纤维的固相微萃取-气相色谱/同位素质谱联用方法测定水中挥发性有机污染物碳同位素。使用浸入式固相微萃取和顶空固相微萃取方法进行实验确定在低浓度条件下最佳δ13C测试方法。通过使用顶空固相微萃取前处理技术进行单体同位素分析分析灵敏度更高,应用CSIA技术对1,2-二氯乙烯,三氯乙烯,四氯化碳进行单体同位素分析,方法的检出限为70μg/L,与样本的标准偏差小于0.3‰。该法适用于水体中微量挥发性有机污染物的同位素组成测定。 相似文献
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气相色谱同位素比值质谱法在线测定天然气稳定碳同位素 总被引:1,自引:0,他引:1
1 引言 色谱同位素比值质谱(GC-IRMS)技术是一种在线分析天然气中轻质烃类组分的新技术。可以在分子水平上连续测定从GC流出的每个化合物的碳同位素组成。在天然气的研究中,碳同位素是一个敏感指标,可信度和测量准确度高。本实验利用GC/C/IRMS联用仪,采用在线分析技术,并在开放体系中瞬间取样,分析了新疆灰岩和四川泥岩样品热模拟气的单体烃碳同位素值,可望为GC-IRMS技术在气/源对比和油气地质勘探中的应用提供参考,如利用模拟气测试的碳同位素比值可被地质上用来进行气一源岩相关研究,判断天然气的来源及源岩的成熟度等。 相似文献
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采用GC-C-IRMS、EA-IRMS和Dual-inlet IRMS 3种稳定同位素比值质谱仪分别对六六六的α、β和γ3种异构体的稳定碳同位素组成进行了分析。对比3种分析系统测定的碳同位素组成数据表明GC-C-IRMS系统能够准确和精确地测定六六六碳同位素组成。应用GC-C-IRMS技术分析了水样品中α-和γ-六六六的碳同位素组成,结果表明六六六在溶解、稀释、萃取、挥发等过程碳同位素组成没有分馏现象。采用GC-C-IRMS技术分析环境样品中持久性有机氯农药稳定碳同位素组成可能得到广泛应用。 相似文献
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静态灼烧氧化法制备有机碳同位素质谱分析样品 总被引:5,自引:0,他引:5
针对目前国内大多数实验室采用密封安瓶法制备有机碳同位素质谱分析样品所存在的不足之处,设计了呈套静态灼氧化法制备有机碳同位素质谱分析样品的实验系统,该系统具有实验精度高,操作方便,经济安全等特点,适合于在国内同位素实验室中推广应用。 相似文献
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建立了同位素稀释高分辨气相色谱-高分辨质谱测定土壤中痕量有机氯农药残留的分析方法。采用加速溶剂法萃取土壤样品,以正己烷/丙酮(体积比为1:1)为提取溶剂,提取液经过Florisil硅土固相萃取小柱净化后,采用高分辨DB-5MS毛细管色谱柱(30 m×0.25 mm×0.25 μm)分离,以保留时间和同位素特征离子丰度比定性,同位素峰面积比定量。实验结果表明,方法的回收率为77.3%~114.5%,相对标准偏差(RSD)≤10.81%(n=5),检出限均小于0.04 pg/g。应用该方法检测某地区表层土壤中的有机氯农药,结果表明该方法适合测定环境土壤背景中痕量有机氯残留。 相似文献
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该文综述了基于液相色谱-高分辨质谱联用(LC-HRMS)技术开展的沉积物和颗粒物中有机污染物分析的研究进展,包括LC-HRMS分析策略、分析流程及其在目标物、可疑物和非目标物分析中的实际应用,重点介绍了高通量分析、新兴污染物筛查、不同数据库的特点及应用、未知化合物鉴定置信水平、数据非依赖性采集和优先级策略等内容,初步探讨了该技术目前存在的问题并对其发展和应用进行了展望,以期进一步提高识别和鉴定工作的效率,更好地开展环境样品中有机污染物的筛查和监测研究。文中涉及的高分辨质谱的相关通用性内容,也为该技术在其他领域的应用提供了一定的参考和启发。 相似文献
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V. A. Roznyatovskii V. V. Roznyatovskii Yu. A. Ustynyuk 《Russian Chemical Bulletin》2004,53(10):2196-2199
The 13C-{1H} and 119Sn-{1H} NMR spectra of hexaethyldistannane were measured and analyzed using an iteration program for the calculation of the complete line shape with correction of a residual inhomogeneity of the magnetic field and phase distortions. Signals of 22 isotopomers containing magnetic isotopes of tin and carbon in different pairwise and triple combinations were identified, and their spectral parameters were determined. The content of isotopes 119Sn, 117Sn, and 115Sn in the molecule was determined with a high accuracy sufficient for the study of isotope effects in chemical reactions.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2102–2104, October, 2004. 相似文献
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Vitali Tugarinov 《Magnetic resonance in chemistry : MRC》2013,51(11):722-728
An approach towards precision NMR measurements of four‐bond deuterium isotope effects on the chemical shifts of backbone amide nitrogen nuclei in proteins is described. Three types of four‐bond 15 N deuterium isotope effects are distinguished depending on the site of proton‐to‐deuterium substitution: 4ΔN(Ni‐1D), 4ΔN(Ni+1D) and 4ΔN(Cβ,i‐1D). All the three types of isotope shifts are quantified in the (partially) deuterated protein ubiquitin. The 4ΔN(Ni+1D) and 4ΔN(Cβ,i‐1D) effects are by far the largest in magnitude and vary between 16 and 75 ppb and ?18 and 46 ppb, respectively. A semi‐quantitative correlation between experimental 4ΔN(Ni+1D) and 4ΔN(Cβ,i‐1D) values and the distances between nitrogen nuclei and the sites of 1H‐to‐D substitution is noted. The largest isotope shifts in both cases correspond to the shortest inter‐nuclear distances. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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对于卟啉碳同位素的测定 ,传统方法 (用HPLC分离出单个卟啉化合物 ,然后燃烧成CO2 进行碳同位素的测定 )需要的样品量大 (几mg)、耗时长 ,限制了其在化学、地球科学中的应用。该文作者建立的方法是通过对卟啉化合物进行衍生化反应 ,以增强卟啉的挥发性 ,使其适用于气相色谱 同位素比值质谱 (GC IRMS)技术。对衍生化反应的整个过程进行了同位素测定 ,证实最终的衍生化硅卟啉与初始的自由基卟啉化合物碳同位素的差值在分析误差范围之内 ,无明显的同位素分馏。 相似文献
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SR-O ISOTOPE SYSTEM OF SOME GRANITOIDS IN CHINA 总被引:1,自引:0,他引:1
Four of Sr- O isotope types can be observed in the graphs of δ~(18)O vs. (~(87)Sr/~(86)Sr)_i accord-ing to our data: (i) closed-system crystallization type: nearly short- vertical line withsimilar initial Sr isotope ratios and small changes of δ~(18)O values(<3‰); (ii) sialic materialremelting type: negative correlations without mantle end member; (iii) crust-mantle contam-ination type: a variety of mixing hyperbolas or straight lines with positive slopes: (iv)water-rock exchange type: irregular distribution. 相似文献
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A. L. Buchachenko 《Russian Chemical Bulletin》1995,44(9):1571-1577
A method for experimental testing of the molecular dynamic functionf(t), which describes the generation of reencounters in a dynamic pair of molecular particles, has been developed. The method is based on the analysis of isotope separation in spin selective reactions of a radical pair. Thef(t) function derived from the solution of the diffusion equation with physically rigorous initial and boundary conditions describes experimental results much better than the well-known Noyes function. Conditions that make it possible to increase the efficiency of isotope separation in spin selective reactions are formulated.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1639–1645, September, 1995.This work was financially supported by the Russian Foundation for Basic Research (Project No. 93-03-05227). 相似文献
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Dr. Gianluca Destro Kaisa Horkka Olivier Loreau David-Alexandre Buisson Lee Kingston Dr. Antonio Del Vecchio Dr. Magnus Schou Dr. Charles S. Elmore Dr. Frédéric Taran Dr. Thibault Cantat Dr. Davide Audisio 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(32):13592-13597
A transition-metal-free carbon isotope exchange procedure on phenyl acetic acids is described. Utilizing the universal precursor CO2, this protocol allows the carbon isotope to be inserted into the carboxylic acid position, with no need of precursor synthesis. This procedure enabled the labeling of 15 pharmaceuticals and was compatible with carbon isotopes [14C] and [13C]. A proof of concept with [11C] was also obtained with low molar activity valuable for distribution studies. 相似文献
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Gianluca Destro Kaisa Horkka Olivier Loreau David‐Alexandre Buisson Lee Kingston Antonio Del Vecchio Magnus Schou Charles S. Elmore Frdric Taran Thibault Cantat Davide Audisio 《Angewandte Chemie (International ed. in English)》2020,59(32):13490-13495
A transition‐metal‐free carbon isotope exchange procedure on phenyl acetic acids is described. Utilizing the universal precursor CO2, this protocol allows the carbon isotope to be inserted into the carboxylic acid position, with no need of precursor synthesis. This procedure enabled the labeling of 15 pharmaceuticals and was compatible with carbon isotopes [14C] and [13C]. A proof of concept with [11C] was also obtained with low molar activity valuable for distribution studies. 相似文献
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Fundamental principles for obtaining mass spectral isotopic distributions are applied to a general computer program that can be used to calculate and present in tabular and graphic form the isotopic contributions for any molecular formula. A unique feature is the retention of the isotopic distribution, exact mass, and absolute abundance for all individual peaks at each mass. Special considerations have been made for the large number of isotopic combinations that occur for many higher mass compounds. The computer program accepts the input of a molecular formula followed by interactive input of a number of parameters that affect the final presentation of the theoretical distribution profile. 相似文献