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Proceedings Paper

Fabrication of a microdevice for continuous monitoring and fast response to isocyanates (TDI) exposure in a working environment
Author(s): A. A. Agbabiaka; Sabarna Mukhopadhyay; D. Mukherjee; Stephen C. Thorpe
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Paper Abstract

Isocyanates, basic starting materials used in automobile and household paints, are classified as respiratory sensitizers by the UK Health and Safety Executive Commission. There are several procedures for the determination of isocyanate concentration, in the working environment, including HPLC, HSLC techniques, which are, however, incapable of continuous monitoring of the working environment of an individual worker. The crucial drawback lies in the fact that these methods only produce an average concentration, inhaled by the worker, during the whole sampling period. Instantaneous sharp exposures cannot be identified at any given time interval. This communication describes the fabrication of metal-free phthalocyanine derivative multilayers and their reaction to TDI exposures in a controlled environment. Thin films of a metal-free phthalocyanine derivative, when exposed to 35 ppb of TDI have been observed to produce alterations in their resistance values. Thirty nm films have shown an average maximum resistance change of approximately 2.3 multiplied by 108 (Omega) while films of approximately 90 nm thickness showed a resistance alteration of approximately 1.5 multiplied by 107 (Omega) , when exposed alternatively to the analyte for 2 minutes followed by fresh air for another 2 minutes to flush the system. The average response times have been calculated to be approximately 30 to 40 seconds. The repeated reactions of the samples were quite remarkable since the literature review of known isocyanate reactions does not indicate reversible reactions of this nature.

Paper Details

Date Published: 6 February 1997
PDF: 6 pages
Proc. SPIE 2968, Optical Organic and Semiconductor Inorganic Materials, (6 February 1997); doi: 10.1117/12.266809
Show Author Affiliations
A. A. Agbabiaka, South Bank Univ. (United Kingdom)
Sabarna Mukhopadhyay, South Bank Univ. (United Kingdom)
D. Mukherjee, South Bank Univ. (United Kingdom)
Stephen C. Thorpe, Health and Safety Executive (United Kingdom)

Published in SPIE Proceedings Vol. 2968:
Optical Organic and Semiconductor Inorganic Materials
Edgar A. Silinsh; Arthur Medvids; Andrejs R. Lusis; Andris O. Ozols, Editor(s)

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