| 摘要 |
PROBLEM TO BE SOLVED: To continuously and accurately measure a sulfuric compound with a low concentration, especially 1 ppm or less, with improved response by using a fuel gas containing hydrogen with a specific concentration and an inert gas. SOLUTION: Hydrogen with 20-70 vol.% and an inert gas are used as a fuel gas. More specifically, a mixed gas of hydrogen with 20-70 vol.% and helium is introduced into a reaction cell 2 via a fuel gas introduction pipe 5. Also air is introduced via a gas introduction pipe 6 for supporting burning to ignite the mixed gas of hydrogen and helium. Then, a sample containing a sulfuric oxide is supplied into hydrogen flame 3 via a sample introduction pipe 4 to generate sulfuric oxide. The generated sulfuric oxide is taken out and is supplied to an ozone oxidation cell 8, and is allowed to react with ozone, thus generating a sulfuric dioxide in an excitation state. Luminous intensity when the sulfuric dioxide being in excitation state returns to a ground state is measured by a photomultiplier 11 and the concentration of the sulfuric compound is calculated from the luminous intensity.
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