Mathew Luebbers1, Adarsh D. Radadia1, Byunghoon Bae2, Junghoon Yeom2, Jea-Hyeong Han3, Ilwhan Oh4, Mark A. Shannon5, and Richard I. Masel6. (1) Chemical and Biomolecular Engineering, University of Illinois, 600 S. Mathews St., Urbana, IL 61801, (2) Department of Mechanical and Industrial Engineering, University of Illinois at Urbana-Champaign, 1206 W. Green St., Urbana, IL 61801, (3) Mechanical and Industrial Engineering, University of Illinois at Urbana-Champaign, 1206 W. Green St., Urbana, IL 61801, (4) Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 294 RAL, MC-712, 600 S. Mathews Ave., Urbana, IL 61801, (5) Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 W. Green Street, Urbana, IL 61801, (6) Chemical Engineering, University of Illinois at Urbana-Champaign, 600 S Mathews, Urbana, IL 61801
For reasons of homeland security as well as a wide variety of other applications, the development of a small, accurate, and portable micro gas chromatograph has become a topic of great interest. Such a device could be used to monitor air samples and separate individual components which allows for several possible applications such as monitoring for a hazardous chemical species. However, to make implementing the device practical, one of the most important demands is that the device components must all behave properly for long periods of time and work extremely consistently over millions of cycles. This is extremely demanding the case of this device because the entire chromatogram detected is expected to take around 4 seconds with peak widths on the order of tens of milliseconds. Any malfunction or degradation in the performance of a component could lead to peak shifting or peak dispersion which if severe enough would make the device unusable.
In this project, the micro gas chromatograph is form by integrating an array of detectors with a microfabricated pump, a microfabricated column, and a microfabricated preconcentrator assembly with microfabricated valves. For the purposes of characterizing the device performance, a set of tests must be run to determine a false-positive rate. The amount of jitter, or peak shifting, seen during the repetition of thousands of testing cycles will be indicative of the expected rate of false-positive responses.
This paper will report on the repetition jittering testing of a number of testing setups. Initially we will test with a commercially available sampling valve and a standard fused silica column. A sample containing a trace vapor will be injected over the course of many thousands of cycles and the peak position will be tracked over all trials. The microfabricated valves and column will then be integrated into this test setup and the same experiment will be repeated. In addition, tests will be performed in which multiple components are separated and tracked over repeated cycles, thus giving a solid feasibility test for the long term operation of the device.