A Monolithically-Integrated μGC Chemical Sensor System

Abstract

Gas chromatography (GC) is used for organic and inorganic gas detection with a range of applications including screening for chemical warfare agents (CWA), breath analysis for diagnostics or law enforcement purposes, and air pollutants/indoor air quality monitoring of homes and commercial buildings. A field-portable, light weight, low power, rapid response, micro-gas chromatography (μGC) system is essential for such applications. We describe the design, fabrication and packaging of μGC on monolithically-integrated Si dies, comprised of a preconcentrator (PC), μGC column, detector and coatings for each of these components. An important feature of our system is that the same mechanical micro resonator design is used for the PC and detector. We demonstrate system performance by detecting four different CWA simulants within 2 min. We present theoretical analyses for cost/power comparisons of monolithic versus hybrid μGC systems. We discuss thermal isolation in monolithic systems to improve overall performance. Our monolithically-integrated μGC, relative to its hybrid cousin, will afford equal or slightly lower cost, a footprint that is 1/2 to 1/3 the size and an improved resolution of 4 to 25%.

Pulsed Discharge Helium Ionization Detector for Highly Sensitive Aquametry

“…We are also fabricating a micro-PDHID (μ-PDHID) with an even better SWAPP, cost, and performance factors. 38 We will integrate the μ-PDHID with our previously reported μGC and micro-sample preconcentrator (μPC), 20 both of which will be coupled to a portable He gas canister, to enable a low cost, hand-portable, field aquametry instrumentation package, for onsite chemical and biological vapors and moisture measurements, in a variety of civilian, medical, and military applications. Progress in these directions is also being enabled by recent reports of other microdischarge photoionization detectors for μGCs.…”

Development of a Mesoscale Pulsed Discharge Helium Ionization Detector for Portable Gas Chromatography

“…The stainless-steel could be passivated further through a variety of commercial processes such as the Silico Steel ® method for improved inertness. The scaled prototype was about 10 cm 3 compared to the commercial PDHID volume of greater than 400 cm 3 , thereby effecting an approximately 40-fold miniaturization. The central, active channel of the baseline prototype design has the same internal diameter as the commercial version (VICI, Valco), but at 17.5 mm in length, it was ~40% shorter.…”

“…2 Miniaturization of GC instruments includes decreasing the footprint of the overall package in order to improve size, weight, and power/portability (SWAPP) factors. We have extensively described the fabrication of a variety of monolithically-integrated micro-GC instrumentation previously, including valves, pumps, heaters, GC columns, sensors, and sample pre-concentrators, [3][4][5][6][7][8][9] for the detection of a broad range of chemical and biological VOCs. 10 Our overarching goal was to deploy a field-portable GC instrumentation package with excellent SWAPP factors.…”

Characterization of a micro-helium discharge detector for gas chromatography

“…Miniaturization offers unique advantages such as light-weight, low power consumption, less reagent usage and innovative architectures apart from lower cost when batch fabricated [14][15][16][17][18][19][20][21][22][23][24][25][26][27]. Stereotypical miniaturization utilizes components fabricated in silicon/glass.…”