%0 Journal Article
%T Measurements of the Weak UV Absorptions of Isoprene and Acetone at 261¨C275 nm Using Cavity Ringdown Spectroscopy for Evaluation of a Potential Portable Ringdown Breath Analyzer
%A Peeyush Sahay
%A Susan T. Scherrer
%A Chuji Wang
%J Sensors
%D 2013
%I MDPI AG
%R 10.3390/s130708170
%X The weak absorption spectra of isoprene and acetone have been measured in the wavelength range of 261¨C275 nm using cavity ringdown spectroscopy. The measured absorption cross-sections of isoprene in the wavelength region of 261¨C266 nm range from 3.65 ¡Á 10 £¿21 cm 2¡¤molecule £¿1 at 261 nm to 1.42 ¡Á 10 £¿21 cm 2¡¤molecule £¿1 at 266 nm; these numbers are in good agreement with the values reported in the literature. In the longer wavelength range of 270¨C275 nm, however, where attractive applications using a single wavelength compact diode laser operating at 274 nm is located, isoprene has been reported in the literature to have no absorption (too weak to be detected). Small absorption cross-sections of isoprene in this longer wavelength region are measured using cavity ringdown spectroscopy for the first time in this work, i.e., 6.20 ¡Á 10 £¿23 cm 2¡¤molecule £¿1 at 275 nm. With the same experimental system, wavelength-dependent absorption cross-sections of acetone have also been measured. Theoretical detection limits of isoprene and comparisons of absorbance of isoprene, acetone, and healthy breath gas in this wavelength region are also discussed.
%K UV absorption cross-sections
%K breath biomarker
%K isoprene
%K acetone
%K CRDS
%U http://www.mdpi.com/1424-8220/13/7/8170