| 摘要 |
PURPOSE:To measure a very small quantity of oxygen with high accuracy by a method wherein the oxygen in a very small quantity in a sample gas is made to react with a white phosphorus vapor of a lower pressure than the saturation vapor pressure of white phosphorus at a normal temperature. CONSTITUTION:First an inlet valve 23 and an outlet valve 26 are closed, while a bypass valve 28 is opened, and a carrier gas is supplied into a reaction chamber 1 through a bypass channel 27 of a carrier gas supply pipe 21. Next a sample gas is subjected to flow-rate regulation by a sample gas flowmeter 9 and supplied into the chamber 1 from a sample gas supply pipe 10. The temperature of a constant temperature bath 22 being maintained at a prescribed temperature, the valve 28 is closed while the valves 23 and 26 are opened, and a white phosphorus vapor obtained through sublimation of solid white phosphorus is supplied, with the carrier gas, into the chamber 1 through the pipe 21. Thereby the oxygen in the sample gas is made to react with the white phosphorus vapor in the carrier gas, so as to emit a light, in the chamber 1. The intensity of emission is detected by a photodetector 7 and a photocurrent is outputted therefrom. The value of this current is collated with the working cure of a standard gas prepared beforehand under the same measuring conditions, and thereby the quantity of the oxygen in the sample gas is measured. |
