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Proceedings Paper

Formaldehyde sensor using non-dispersive UV spectroscopy at 340nm
Author(s): J. J. Davenport; J. Hodgkinson; J. R. Saffell; R. P. Tatam
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Paper Abstract

Formaldehyde is a volatile organic compound that exists as a gas at room temperature. It is hazardous to human health causing irritation of the eyes, nose and throat, headaches, limited pulmonary function and is a potential human carcinogen. Sources include incomplete combustion, numerous modern building materials and vehicle fumes. Here we describe a simple method for detecting formaldehyde using low resolution non-dispersive UV absorption spectroscopy for the first time. A two channel system has been developed, making use of a strong absorption peak at 339nm and a neighbouring region of negligible absorption at 336nm as a reference. Using a modulated UV LED as a light source and narrowband filters to select the desired spectral bands, a simple detection system was constructed that was specifically targeted at formaldehyde. A minimum detectable absorbance of 4.5 × 10-5 AU was estimated (as ΔI/I0), corresponding to a limit of detection of approximately 6.6 ppm for a 195mm gas cell, with a response time of 20s. However, thermally-induced drift in the LED spectral output caused this to deteriorate over longer time periods to around 30 ppm or 2 × 10-4 AU.

Paper Details

Date Published: 15 May 2014
PDF: 6 pages
Proc. SPIE 9141, Optical Sensing and Detection III, 91410K (15 May 2014); doi: 10.1117/12.2052460
Show Author Affiliations
J. J. Davenport, Cranfield Univ. (United Kingdom)
J. Hodgkinson, Cranfield Univ. (United Kingdom)
J. R. Saffell, Alphasense (United Kingdom)
R. P. Tatam, Cranfield Univ. (United Kingdom)

Published in SPIE Proceedings Vol. 9141:
Optical Sensing and Detection III
Francis Berghmans; Anna G. Mignani; Piet De Moor, Editor(s)

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