NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Aqueous nitrite ion determination by selective reduction and gas phase nitric oxide chemiluminescenceAn improved method of flow injection analysis for aqueous nitrite ion exploits the sensitivity and selectivity of the nitric oxide (NO) chemilluminescence detector. Trace analysis of nitrite ion in a small sample (5-160 microL) is accomplished by conversion of nitrite ion to NO by aqueous iodide in acid. The resulting NO is transported to the gas phase through a semipermeable membrane and subsequently detected by monitoring the photoemission of the reaction between NO and ozone (O3). Chemiluminescence detection is selective for measurement of NO, and, since the detection occurs in the gas-phase, neither sample coloration nor turbidity interfere. The detection limit for a 100-microL sample is 0.04 ppb of nitrite ion. The precision at the 10 ppb level is 2% relative standard deviation, and 60-180 samples can be analyzed per hour. Samples of human saliva and food extracts were analyzed; the results from a standard colorimetric measurement are compared with those from the new chemiluminescence method in order to further validate the latter method. A high degree of selectivity is obtained due to the three discriminating steps in the process: (1) the nitrite ion to NO conversion conditions are virtually specific for nitrite ion, (2) only volatile products of the conversion will be swept to the gas phase (avoiding turbidity or color in spectrophotometric methods), and (3) the NO chemiluminescence detector selectively detects the emission from the NO + O3 reaction. The method is free of interferences, offers detection limits of low parts per billion of nitrite ion, and allows the analysis of up to 180 microL-sized samples per hour, with little sample preparation and no chromatographic separation. Much smaller samples can be analyzed by this method than in previously reported batch analysis methods, which typically require 5 mL or more of sample and often need chromatographic separations as well.
Document ID
20040112230
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Dunham, A. J.
(University of Colorado Boulder 80309-0215, United States)
Barkley, R. M.
Sievers, R. E.
Clarkson, T. W.
Date Acquired
August 21, 2013
Publication Date
January 1, 1995
Publication Information
Publication: Analytical chemistry
Volume: 67
Issue: 1
ISSN: 0003-2700
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: ATM-9115295
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Environmental Health
Non-NASA Center

Available Downloads

There are no available downloads for this record.
No Preview Available