Portable Fourier transform infrared spectrometer for use as a gas analyser in industrial hygiene

Abstract

A portable, real-time, gas analyser (GASMET), based on the Fourier transform infrared (FTIR) principle, was compared with the adsorption tube method in four factories using organic solvent mixtures. The usefulness of the gas analyser data was also evaluated from the point of view of preventive measures. The gas analyser incorporates the use of a low-resolution FTIR spectrometer, a 486 computer and a temperature-controlled gas cell. The gas analyser was calibrated with the expected pure compounds and solvent mixtures in different concentrations. CALCMET software based on a modified classical least-squares lineshape fitting is used for the identification and quantification of compounds. The typical detection limit of the gas analyser is about 1 mg m^–3. The correlation of the total hygienic effect between the gas analyser and the adsorption tubes was good (correlation coefficient = 0.978). With small concentrations of some single compounds, some discrepancy occurs between the results obtained with the two methods. Continuous monitoring with the gas analyser reveals the worktasks with exposure peaks and makes precise preventive measures possible.