SECOND DERIVATIVE SPECTROSCOPY AND ITS APPLICATION TO AIR POLLUTION IDENTIFICATION AND MEASUREMENT
Loading...
Date
1972
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
A derivative spectrometer is sensitive to changes in spectral intensity over a narrow wavelength interval. Specifically, a second derivative spectrometer senses the curvature of the incident spectral intensity, providing an output voltage signal proportional to the second derivative of intensity with respect to wavelength. When such an instrument is combined with a multi-pass White cell, a unique trace gas analyzer results. The analyzer, operating within the middle ultraviolet spectral region, provides a highly amplified derivative spectrum of any molecular narrow band absorption which is used for trace gas identification. The intensity of any peak within a spectrum is proportional to the trace gas concentration. Such an analyzer, utilizing a 20 meter pathlength White cell, is presently being used to automatically monitor ambient air for $SO_{2}$, NO, $NO_{2}$ and $O_{3}$ with minimum detectable concentration limits in the part per billion range.
Description
Author Institution: Spectrometrics of Florida, Inc.