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Gas chromatography.

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Continuous Monitoring Of Volatile Organic Compounds Using Microtrap Based Gas Chromatographic Systems, Yonghua Xu May 1996

Continuous Monitoring Of Volatile Organic Compounds Using Microtrap Based Gas Chromatographic Systems, Yonghua Xu

Dissertations

Continuous analysis allows a representative portion of a sample to flow continuously through an analytical instrument, which gives analytical information with little or no delay in time. A microtrap is a small diameter tube packed with adsorbents in series. When a gaseous sample containing volatile organic compounds (VOCs) flows through the microtrap, the VOCs can be trapped selectively by adsorbents. Then a pulse of electrical current is applied to the microtrap. This rapid heating results in a desorption that can act as a sharp injection for GC separation. Thus the microtrapped sample is the total amount of VOC present in …


Continuous Monitoring Of Volatile Organic Compound Emissions Using Microtrap Based Injection Technique And Gas Chromatography, Wenjun Chen Jan 1996

Continuous Monitoring Of Volatile Organic Compound Emissions Using Microtrap Based Injection Technique And Gas Chromatography, Wenjun Chen

Theses

A microtrap is made by packing a small diameter tubing with an adsorbent. The microtrap can be rapidly heated with a pulse of electrical current resulting in a sharp desorption that can act as an injection for GC separation. The microtrap can be used in several configurations to concentrate and inject sample in continuous, on-line monitoring system.

In this research a laboratory scale catalytic incinerator was set up and volatile organic compounds in the incinerator effluents were monitored using the microtrap based injection systems. The detection systems used were gas chromatography and nonmethane organic carbon (NMOC) analyzer. Conventional sample valve, …


Measurement Of Oxygenated Volatile Organic Compounds Using The Thermionic Ionization Detector, Wanfang Li May 1994

Measurement Of Oxygenated Volatile Organic Compounds Using The Thermionic Ionization Detector, Wanfang Li

Theses

A thermionic ionization detector (TID) consists of a catalytically active, low work function heated source. It responds to molecules with high electron affinity which can extract electrons from the surface of the source to form negative ions. TID has been used as selective detectors for nitrogen and phosphorous compounds (NPD). In this research, a TID has been used for selective detection of oxygenated volatile organic compounds (VOCs). The response of the TID to different oxygenated and chlorinated VOCs compounds was studied. To evaluated its performance, the analysis was done using a FID in parallel with the TID. For most of …