OZONE GAS-PHASE CHEMILUMINESCENCE FOR SILANE AND ITS APPLICATION TO THE DETERMINATION OF SILICATE IN NATURAL-WATERS

Chemiluminescence emission generated by mixing silane with ozone was i nvestigated for the determination of silicate in natural water. This c hemiluminescence spectra extends 400-850 nm providing a maximum at 600 nm. Chemiluminescence spectra obtained by mixing diborane, and ozone were also shown. For the purpose of generating silane from the aqueous solution of silicate, the following procedure was adopted: The sample solution was dried and mixed homogeneously with powdered lithium alum inum hydride in a Teflon tube or a molybdenum boat. When this mixture was heated at 200-degrees-C, 97 +/- 3% of silicate in the sample was r educed to silane. After the generated silane was collected in the trap , the silane was mixed with ozone, and chemiluminescence was detected directly by a photomultiplier. The calibration curve was linear from 1 to 500 mug Si, and the detection limit was 0.5 mug of Si for this met hod. Phosphorus and arsenic give the positive interference, which is, however, negligible for the practical analysis of natural waters. The analytical results for river waters and seawaters (the Tokyo Bay and t he North Pacific Ocean) are in good agreement with those confirmed by molybdenum yellow colorimetry.