出版社：National Institute of Occupational Safety and Health
摘要：A method for determining atmospheric diborane in concentrations higher than 1/10 of TLV, i.e., 0.01 ppm, has been developed using the adsorption sampling method. Silica gel impregnated with potassium permanganate, synthetic resin activated carbon im-pregnated with or without mercury(II) chloride and activated carbon impregnated with chromate salt showed adsorption capacities larger than 18l of 3 ppm diborane test gas when the test gas was drawn at 300 ml /min. Complete desorption of the adsorbed diborane was possible only from silica gel impregnated with potassium permanganate into a hydroxylamine hydrochloride solution. As methods for determining the desorbed boron, both the chromo-tropic acid-HPLC method and ICP-AES were applied. The former was more sensitive, but the latter was less influenced by coexistent substances. The most sensitive and reproducible procedure for diborane determination was as follows : diborane is collected with silica gel impregnated with potassium permanganate (0.05% (w/w)) and desorbed into hydroxylamine hydrochloride solution (400 μg/ml) followed by the determination of boron by the chromo-tropic acid-HPLC method. When diborane in 3l of 0.1 ppm test gas was collected, the desorption efficiency was 105.3% with an RSD of 13.5%. The limit of quantitation of this method was 0.0026 ppm in 3l air. Much lower concentrations can be determined by sampling larger amounts of air.
