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Title: Investigations into the chemical structure based selectivity of the microfabricated nitrogen-phosphorus detector

The nitrogen and phosphorus atoms are constituents of some of the most toxic chemical vapors. Nitrogen-phosphorus gas chromatograph detectors (NPDs) rely on selective ionization of such compounds using ionization temperatures typically greater than 600 °C. NPDs have previously been reported to be 7*104× and 105× more sensitive for nitrogen and phosphorus, respectively, than for carbon. Presented here is an investigation of the structure-based selectivity of a microfabricated nitrogen-phosphorus detector (μNPD). The μNPD presented here is smaller than a dime and can be placed in a system that is 1/100th the size of a commercial NPD. Comparison of responses of such devices to homologous anilines (p-methoxyaniline, p-fluoroaniline, and aniline) revealed that detection selectivity, determined by the ratio of μNPD to nonselective flame ionization detector (FID) peak areas, is correlated with acid disassociation pKa values for the respective analine. Selectivity was determined to be greatest for p-methoxyaniline, followed by p-fluoroaniline, with aniline having the smallest response. The limit of detection for a nitrogen containing chemical, p-methoxyaniline, using the μNPD was determined to be 0.29 ng compared to 59 ng for a carbon chemical containing no nitrogen or phosphorus, 1,3,5-trimethybenzene. The μNPD presented here has increased detection for nitrogen and phosphorus compared tomore » the FID and with a slight increase in detection of carbon compounds compared to commercial NPD's sensitivity to nitrogen and carbon.« less
Authors:
 [1] ;  [2] ;  [2] ;  [2]
  1. Univ. of New Mexico, Albuquerque, NM (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
  2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
OSTI Identifier:
1236476
Report Number(s):
SAND--2015-2012J
Journal ID: ISSN 0925-4005; PII: S0925400515304974
Grant/Contract Number:
AC04-94AL85000
Type:
Accepted Manuscript
Journal Name:
Sensors and Actuators. B. Chemical
Additional Journal Information:
Journal Volume: 224; Journal Issue: C; Journal ID: ISSN 0925-4005
Publisher:
Elsevier
Research Org:
Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION pKa; aniline; nitrogen; phosphorus; chemical detector