1988 Volume 26 Issue 4 Pages 225-237
An adsorption sampling method for airborne silane was developed using active carbon made from synthetic thermosetting resin beads, and an ac-companying procedure to determine silane concentration was established. The resin active carbon had very low silicon contamination (0.31-3.14 μg Si/g), and its ca-pacity for adsorbing silane was improved by impregnating sodium hydroxide up to 20 wt.% of the carbon. This sodium hydroxide-impregnated-active carbon (200 mg) had the capacity to adsorb 5 ppm of silane in 6l of air drawn at the rate of 200 m//min, without breakthrough. To quantify the silane, the adsorbed silane was desorbed into 4 ml of water at 80°C with more than 90% efficiency, and the final solution of silicate ions in the sodium hydroxide solution was analyzed by graphite furnace AAS with a pyrocoated graphite tube. From the results, adsorp-tion sampling tubes were formed by packing 200 mg and 100 mg of the resin active carbon impregnated with sodium hydroxide as two separate beds in a polyethylene tube of 4 mm inside diameter. The lower limit of slilane determination by this method was less than 1 ppm in 1l of air.
