title: Development of a Mesoscale Pulsed Discharge Helium Ionization Detector for Portable Gas Chromatography.
abstract: Miniaturization of gas chromatography (GC) instrumentation enables field detection of volatile organic compounds (VOCs) for chembio-applications such as clandestine human transport and disease diagnostics. We fabricated a mesoscale pulsed discharge helium ionization detector (micro-PDHID) for integrating with our previously described mini-GC hardware. Stainless steel electrodes fabricated by photochemical etching and electroforming facilitated rapid prototyping and enabled nesting of inter-electrode insulators for self-alignment of the detector core during assembly. The prototype was ∼10 cm(3) relative to >400 cm(3) of a commercial PDHID, but with a comparable time to sweep a VOC peak from the detector cell (170 ms and 127 ms, respectively). Electron trajectory modeling, gas flow rate, voltage bias, and GC outlet location were optimized for improving sensitivity. Despite 40-fold miniaturization, the micro-PDHID detected 18 ng of the human emanation, 3-methyl-2-hexenoic acid with <3-fold decrease in sensitivity relative to the commercial detector. The micro-PDHID was rugged and operated for 9 months without failure.
authors.affiliation: Bio/Chem/Physical Microsensors Department, Sandia National Laboratories.
authors.forename: Ronald P
authors.initials: RP
authors.lastname: Manginell
authors.forename: Curtis D
authors.initials: CD
authors.lastname: Mowry
authors.forename: Adam S
authors.initials: AS
authors.lastname: Pimentel
authors.forename: Michael A
authors.initials: MA
authors.lastname: Mangan
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Moorman
authors.forename: Elizabeth S
authors.initials: ES
authors.lastname: Sparks
authors.forename: Amy
authors.initials: A
authors.lastname: Allen
authors.forename: Komandoor E
authors.initials: KE
authors.lastname: Achyuthan
mesh_terms: D002208:Caproates / Q000032:analysis; D002849:Chromatography, Gas / Q000295:instrumentation*; D004566:Electrodes; D006371:Helium / Q000737:chemistry*; D006801:Humans; D008904:Miniaturization; D013193:Stainless Steel
chemical_list: D002208:Caproates; D013193:Stainless Steel; D006371:Helium; C004807:trans-3-methyl-2-hexenoic acid