Report on a microprocessor-based infrared analyzer.
Burroughs GE; Woodfin WJ
Appl Ind Hyg 1988 Dec; 3(12):R2-R4
A single beam, microprocessor based spectrometer, the Miran-1B which could be preprogrammed for the measurement of many substances in the workplace was described. Test concentrations were generated in the laboratory for four compounds of current interest in occupational health studies: carbon-dioxide (124389) (CO2), carbon-monoxide (630080) (CO), ethylene-oxide (75218), and nitrous-oxide (10024972). Excluding measurements for ethylene-oxide, the measurements taken by the Miran-1B were usually within the plus or minus 25 percent criterion established by NIOSH Standards Completion Program as acceptable. Measurements of ethylene-oxide on the other hand ranged from 78 percent below to 18 percent above the reference values. The authors suggest that much of the error encountered may be due to the user's unfamiliarity with the instrument and that the ability to perform analyses may improve with experience. Interference between CO and CO2 was reasonable. The microprocessor permits calibration of this instrument at a maximum of five analytical concentrations and forces the second degree regression curve of these data through zero. Measurement of CO2 concentrations above 1000 parts per million was not practical with this instrument unless a secondary analytical wavelength was available. As with any infrared instrument, the user must be aware of other contaminants in the environment to determine if overlapping absorption bands exist with the analyte of interest.
NIOSH-Author; Chemical-analysis; Analytical-methods; Air-sampling-equipment; Air-quality-monitoring; Toxic-gases; Workplace-studies; Analytical-chemistry
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Applied Industrial Hygiene