Ultrahigh-speed chromatography and virtual chemical sensors for detecting explosives and chemical warfare agents
Ultrahigh-speed chromatography and virtual chemical sensors for detecting explosives and chemical warfare agents
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DOI：
10.1109/jsen.2005.850990
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发表时间：
2005-08-01
影响因子：
4.3
通讯作者：
Viswanathan, S
中科院分区：
文献类型：
--
作者：
Staples, EJ;Viswanathan, S
有机化合物的色谱分离是产生时间分辨化学光谱或色谱图的众所周知的方法。使用 10-100 米色谱柱的传统色谱法速度较慢，通常需要几分钟到几小时，而使用短电阻加热金属色谱柱的超高速色谱法仅需要几秒钟。描述了使用表面声波 (SAW) 谐振器测量洗脱化合物质量的超高速气相色谱仪的性能。电阻加热的 1 米毛细管柱以高达 20 摄氏度/秒的速率进行闭环温度编程，可生成近乎实时的 10 秒色谱图，其中化学光谱峰宽以毫秒为单位测量。洗脱的化学物质被物理吸附在未涂层的 SAW 谐振器上，频率偏差与时间的关系产生洗脱的质量与时间的色谱图。频率对时间的导数产生柱通量的质量/单位时间色谱图，其用于测量洗脱化合物的保留时间。本文描述了通过将特定目标化学品（例如爆炸物和化学战剂）的保留时间索引到正烷烃标准品的保留时间来生成独立的化学光谱数据库的仪器和过程。它还表明，分配以特定索引为中心的时间窗口可用于为特定化合物创建非重叠虚拟传感器阵列。重复的高速色谱测量使虚拟传感器读数能够近乎实时地更新。这项工作清楚地证明，针对爆炸物和化学战剂的虚拟化学传感器阵列可以检测到万亿分之一浓度的这些化合物，且检测概率高，误报概率低。
Chromatographic separation of organic compounds is a well-known method of producing time-resolved chemical spectra or chromatograms. Whereas conventional chromatography using 10-100-m columns is slow, often requiring minutes to hours, ultrahigh-speed chromatography with short resistively heated metal columns requires only seconds. The performance of an ultrahigh-speed gas chromatograph using a surface acoustic wave (SAW) resonator to measure the mass of eluted chemical compounds is described. Closed-loop temperature programming of a resistively heated 1-m capillary column at rates as high as 20 degrees C/s produces near real-time, 10-s chromatograms with chemical spectra peak widths measured in milliseconds. Eluted chemicals are physically adsorbed on an uncoated SAW resonator and frequency deviation versus time produces an eluted mass versus time chromatogram. The derivative of frequency versus time produces a mass/unit time chromatogram of column flux, which is used to measure the retention times of eluted compounds. This paper describes the instrument and process where independent database of chemical spectra are produced by indexing the retention time of specific target chemicals (e.g., explosives and chemical warfare agents) to the retention times of n-alkane standards. It is also shown that assigning time windows centered about specific indices can be used to create arrays of nonoverlapping virtual sensors for specific compounds. Repeated high-speed chromatographic measurements enable virtual sensor readings to be updated in near real time. This work clearly proves that arrays of virtual chemical sensors specific to explosive and chemical warfare agents can detect part per trillion levels of these compounds with high probability of detection and low probability of false alarm.