Prototype for in situ detection of atmospheric NO3 and N2O5 via laser-induced fluorescence

Environ Sci Technol. 2003 Dec 15;37(24):5732-8. doi: 10.1021/es034507w.

Abstract

We describe a prototype designed for in situ detection of the nitrate radical (NO3) by laser-induced fluorescence (LIF) and of N2O5 by thermal dissociation followed by LIF detection of NO3. An inexpensive 36 mW continuous wave multi-mode diode laser at 662 nm is used to excite NO3 in the B2E'(0000) <-- X2A'2(0000) band. Fluorescence is collected from 700 to 750 nm. The prototype has a sensitivity to NO3 of 76 ppt for a 60 s integration with an accuracy of 8%. Although this sensitivity is adequate for studies of N205 in many environments, it is much less sensitive (about 300 times) than expected based on a comparison of previously measured photophysical properties of NO2 and NO3. This implies much stronger nonradiative coupling of electronic states in NO3 than in NO2.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Environmental Monitoring / methods*
  • Equipment Design
  • Fluorescence
  • Lasers
  • Nitrates / analysis*
  • Nitrogen Oxides / analysis*
  • Sensitivity and Specificity

Substances

  • Nitrates
  • Nitrogen Oxides
  • nitrogen pentoxide