Laboratory Evaluation of a Colorimetric Hydrazine Dosimeter
Abstract
A passive, colorimetric dosimeter badge was manufactured for NASA by GMD Systems. The badge consisted of two indicators: para- dimethylaminobenzaldehyde (PDAB) and vanillin. When exposed to hydrazine or monomethylhydrazine (MMH), the PDAB turns orange and the vanillin turns yellow. The intensity of the color is proportional to the concentration in the environment. A color wheel was also manufactured to evaluate the color and estimate the dose of hydrazine for each indicator. The laboratory investigations and the preliminary results of the field test indicate that the badge is qualitatively accurate with few interferences. The badges were exposed for sample times between 0.25 and 16 hours at different concentrations of hydrazine and MMH. The badges were evaluated for linearity, relative humidity effects, and interferences. The evaluation was conducted at the Naval Research Laboratory and Wiltech at the Kennedy Space Center. The badges responded with a measurable color change in each test. At low dose and short sample times, there was much scatter in the dose measured. The badges saturated, exceeding the darkest color on the color wheel after 8 TLV-hours. Relative humidity has little effect on the badge responses. Sunlight was an interferent for PDAB, turning it yellow. Tobacco smoke was an interferent for vanillin, turning it pink-purple. (JG)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 12, 1990
- Accession Number
- ADA223208
Entities
People
- Ardell Thurow
- J. R. Wyatt
- Karen P. Crossman
- P. T. Carver
- S. L. Rose- Pehrsson
Organizations
- United States Naval Research Laboratory