Exploiting Charge-Transfer Complexation for Selective Measurement of Gas-Phase Olefins with Nanoparticle-Coated Chemiresistors

Details

• Personal Author:
  Rowe MP ; Steinecker WH ; Zellers ET
• Description:
  Charge-transfer-mediated olefin-selective sensing by use of chemiresistors (CR) coated with composite films of n-octanethiolate-monolayer-protected gold nanoparticles (C8-MPN) and each of several square-planar PtCl2(olefin)(pyridine) coordination complexes is described. Where the gas-phase olefin analyte differs from that initially coordinated to Pt, olefin substitution occurs and is accompanied by a persistent shift in the composite film resistance. Commensurate changes in film mass are also observed with a similarly coated thickness shear mode resonator. Regeneration is possible by exposure to the initially complexed olefin gas or vapor. If the olefin analyte is the same as that initially coordinated to Pt, then a reversible charge-transfer interaction occurs that is accompanied by a decrease in film resistance (increase in film mass), which recovers spontaneously after removal of the olefin from the atmosphere above the sensor. This behavior differs from that of MPN-coated CRs lacking such Pt complexes, which invariably yield resistance increases upon exposure to nonpolar vapors. Red shifts in the UV-vis absorbance spectra of the PtCl2(olefin)(pyridine) complexes in solution upon addition of free olefin support the hypothesis that Pt-olefin coordination in the composite films creates temporary low-resistance pathways that compete effectively with the concurrent increase in tunneling resistance associated with swelling-induced separation of C8-MPN cores. Structurally analogous non-olefins produce only increases in film resistance. Selective measurement of styrene, ethylene, 1-octene, and 1,3-butadiene is illustrated. Olefin detection limits are reduced as much as 23 000-fold by inclusion of the corresponding Pt complex in the CR interface film. Composite films suffer a gradual loss of selectivity from decomposition of the Pt-olefin complex, apparently facilitated by a Au-Pt charge transfer. [Description provided by NIOSH]
• Subjects:
  Environmental Monitoring Occupational Health Safety
• Keywords:
  Air-quality-measurement Air-quality-monitoring Analytical-instruments Analytical-processes Gas-chromatography Gases Nanotechnology Organic-compounds Sampling-equipment Sampling-methods
• ISSN:
  0003-2700
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  Michigan ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  79
• Issue:
  3
• NIOSHTIC Number:
  nn:20031780
• Citation:
  Anal Chem 2007 Feb; 79(3):1164-1172
• Contact Point Address:
  Center for Wireless Integrated MicroSystems, Department of Chemistry, and Department of Environmental Health Sciences, University of Michigan, 109 South Observatory Street, Ann Arbor, Michigan 48109
• Federal Fiscal Year:
  2007
• Performing Organization:
  University of Michigan, Ann Arbor
• Peer Reviewed:
  True
• Start Date:
  19980930
• Source Full Name:
  Analytical Chemistry
• End Date:
  20060531
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:ff6ad9f8235cf3b223f69633df3f5db4940667fcb80b4e97043c824a6c6bd8593ef844b27f2389067a41ae1f2bb43aa725a14f65c3dc94591f82d605f620c117
• Download URL:
  https://stacks.cdc.gov/view/cdc/185942/cdc_185942_DS1.pdf
• File Type:
  [PDF - 146.32 KB ]