DEVELOPMENT OF A MONITORING TAPE FOR CARB ON-MONOXIDE

A porous cellulose tape coated with a silica gel was impregnated with a coloring solution which included palladium sulfate, sulfurous acid a nd glycerin. Palladium sulfite on the tape surface was reduced to pall adium colloid by carbon monoxide. The intensity of the formed stain co uld be measured by an optics system to determine the concentration of carbon monoxide in the sample. A linear relation was obtained between relative intensity and concentration of carbon monoxide in the range o f 3 to 100 ppm at a sampling time of 1 min and a flow rate of 250 ml/m in. The response for hydrogen sulfide was 38 times that for carbon mon oxide. When the sample contains hydrogen sulfide, the sample is passed through a column packed with lead acetate to remove the hydrogen sulf ide. No responses for ammonia (40 ppm), nitrogen dioxide (10 ppm) and ethanol (5%) were observed.