Summary

定量检测痕量爆炸物蒸气通过程序升温脱附 - 气相色谱 - 电子捕获检测器

Published: July 25, 2014
doi:

Summary

微量TNT和RDX的收集吸附剂填充热脱附管爆炸蒸汽是用连接到GC用电子捕获检测器程序升温脱附系统进行分析。仪器分析是结合直接液相沉积法,以减少样品变性和账户仪器漂移和损失。

Abstract

的解决方案标准的直接液体沉积到吸附剂填充的热脱附管用于跟踪爆炸性气体样品的定量分析。直接液体沉积方法产生蒸气样品的分析和解决方案的标准分析之间具有更高的保真度比使用单独的注射方法,蒸汽和溶液, ,收集在小瓶中的溶液制备的蒸气收 ​​集管和标准样品。此外,该方法可占仪器仪表的损失,这使得它非常适合最大限度地减少可变性和定量的微量化学检测。气相色谱电子捕获检测器是一个仪表配置硝基能源,如TNT和RDX,由于其相对高的电子亲和势敏感。然而,这些化合物的蒸气定量是困难而不可行的蒸气的标准。因此,我们消除蒸气标准的要求,结合使用直接液体沉积协议分析跟踪爆炸性蒸气样品的仪器的灵敏度。

Introduction

气相色谱法(GC)是分析化学的核心仪器分析技术,可以说是一样普及,因为在一个化学实验室电热板或平衡。气相色谱仪,可用于制备,鉴定和定量多种化学化合物的组成,可被耦合到各种探测器,如火焰离子化检测器(FID的),光离子化检测器(PID),热导检测器(的TCD的),电子捕获检测器(ECD的),和质谱仪(MS),根据不同的被分析物,方法和应用。样品可以通过一个标准的分流/不分流进样口与小样本的解决方案,专业的顶空分析入口,固相微萃取(SPME)注射器,或热脱附系统时推出。 GC-MS往往是在可替代的或新出现,检测技术,因为它的效用,柔韧性的确认和验证的应用程序中使用的标准技术,与既定的化学数据库和图书馆1识别电源– 7 GC和其相关的采样和检测元件是理想的常规化学分析和更专业的,具有挑战性的分析应用。

越来越多的关注军事,国土安全,和商业企业的分析应用是跟踪爆炸性气体的检测,以检测包括定性和定量。爆炸物痕量气体探测是一种独特的分析化学的挑战,因为分析物,如2,4,6 – 三硝基甲苯(TNT)和环三亚甲基三(RDX)的物理性质,使它们特别难以处理和单独使用更广泛的,更通用的化学分析方法。相对较低的蒸气压和分份每百万体积(ppm的V)饱和蒸气浓度,结合相对高粘着系数,necessit吃了专项抽检协议,仪器仪表,定量方法8 – 12耦合到电子捕获检测器(ECD)或质谱仪(MS)在气相色谱是一种有效的方法,定量分析物爆炸,特别是二硝基甲苯(DNT),TNT和RDX ,6,13 –因为其相对较高的电子亲和力的17 GC-ECD为硝基能量化合物特别有用。美国环境保护署(EPA)已建立的标准方法对炸药分析物检测用GC-ECD和GC-MS,但这些方法都集中于在溶液中的样品,如地下水,并收集在蒸汽相中没有样品。2 ,18 – 23为了检测爆炸性蒸气,替代取样协议必须被使用,如蒸汽收集用吸附剂填充的热脱附样品管,但定量地检测,由于缺乏标准的蒸气仍难以一ND校准方法,不占样品管和仪表的损失。

最近,采用热脱附系统与冷却入口系统(TDS-CIS),耦合到GC-ECD定量方法已经被开发用于TNT和RDX蒸气。24,25与TDS-CIS-GC-ECD仪器相关联的损失痕量爆炸物蒸气进行了表征,并计入例如校准曲线采用直接液相沉积法到吸附剂填充热脱附样品管。然而,文献集中在表征仪器和方法的发展,但实际上从未采样,分析,定量或爆炸性蒸气,唯一的解决方案的标准。这里,重点是协议取样和定量爆炸性蒸气。协议和方法可扩展到其它分析物和痕量爆炸物蒸气,如季戊四醇四硝酸酯(PETN)。

Protocol

1,仪器准备确保仪器,烤箱,和探测器都是在室温。关闭气流入口和检测器。 从GC上取下的TDS。查阅制造商的用户手册,仪器专用程序。 从独联体进口取出TDS适配器和独联体取出内胆。 检查独联体国家进口的颗粒和碎片,而衬垫被删除。清洁任何可见的碎片用压缩空气,或优选氮气。 附加一个新的石墨密封垫圈使用的套圈对班轮结合由制造商提供工具和说明?…

Representative Results

获得定量结果跟踪爆炸性气体样品开始建立的校准曲线使用的解决方案标准的直接液相沉积法到样品管占亏损仪器和解决方案的标准和蒸气样品之间的差异的TDS-CIS-GC-ECD检测仪器。在TDS-CIS-GC-ECD的仪器和方法,用于TNT和RDX微量分析进行了详细的先前描述的其他地方,但仪器参数列于表1中 。24,25在这里, 图1显示了使用一系列色谱图中得到的发表于表1的…

Discussion

再现性对于使用直接液相沉积法与TDS-CIS-GC-ECD仪器仪表,相对标准偏差(RSD)跟踪易燃易爆气体的定量分析的一个关键属性是经常被用来作为衡量标准的重现性。我们经历了相对标准偏差之间和内部样本的TNT炸药约5%,而RDX 10%的重现性。 15%以上的任何RSD作为一个指标来检查变化,以减少该协议的有效性常见的来源。变异来源已导致不可接受的相对标准偏差在过去在下面的讨论中被突出显示。 …

Disclosures

The authors have nothing to disclose.

Acknowledgements

财政支持由国土安全科学部和技术局提供。

Materials

Name of Material/ Equipment Company Catalog Number Comments/Description
2,4,6-Trinitrotoluene (TNT) Accu-Standard M-8330-11-A-10X 10,000 ng μL-1
Cyclotrimethylenetrinitramine (RDX) Accu-Standard M-8330-05-A-10X 10,000 ng μL-1
3,4-Dinitrotoluene (3,4-DNT) Accu-Standard S-22988-01 1000 ng μL-1
Tenax® TA Vapor Sample Tubes Gerstel 009947-000-00 Tenax® 60/80
CIS4 Liner Gerstel 014652-005-00
Transfer Line Ferrule Gerstel 001805-008-00
Inlet Liner Ferrule Gerstel 001805-040-00
CIS4 Ferrule Gerstel 007541-010-00
ECD Detector Ferrule Aglient 5181-3323
DB5-MS Column Res-Tek 12620

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Cite This Article
Field, C. R., Lubrano, A., Woytowitz, M., Giordano, B. C., Rose-Pehrsson, S. L. Quantitative Detection of Trace Explosive Vapors by Programmed Temperature Desorption Gas Chromatography-Electron Capture Detector. J. Vis. Exp. (89), e51938, doi:10.3791/51938 (2014).

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