Gas analyzing method
There is provided a gas analyzing method capable of analyzing impurities in a sample gas with high accuracy by reducing the influence of water present in a gas cell. The gas analyzing method is a method for analyzing the impurities contained in the sample gas, and includes: a pretreatment step of reducing the partial pressure of water in a gas cell ( 10 ) into which the sample gas is introduced to 10 Pa or less; and an analysis step of introducing the sample gas into the gas cell ( 10 ) in which the pretreatment step has been carried out and detecting the impurities by Raman spectroscopy.
1 . A method for analyzing impurities contained in a sample gas, comprising:
a pretreatment step of reducing a partial pressure of water in a gas cell into which the sample gas is introduced to 10 Pa or less; and
an analysis step of introducing the sample gas into the gas cell in which the pretreatment step has been carried out and detecting the impurities by Raman spectroscopy;
wherein the pretreatment step comprises not reducing the partial pressure of water for at least one selected from optical paths of an excitation light path and an optical path of a Raman scattered light.
2 . The gas analyzing method according to claim 1 , wherein the pretreatment step is a step of purging an inside of the gas cell with a dry gas.
3 . The gas analyzing method according to claim 1 , wherein the impurity is at least one of a fluorine gas, a chlorine gas, a bromine gas, hydrogen fluoride, hydrogen chloride, hydrogen bromide, water, and carbon dioxide.
4 . The gas analyzing method according to claim 1 , wherein the sample gas contains at least one of a fluorine compound, a chlorine compound, and a bromine compound.
5 . The gas analyzing method according to claim 2 , wherein the impurity is at least one of a fluorine gas, a chlorine gas, a bromine gas, hydrogen fluoride, hydrogen chloride, hydrogen bromide, water, and carbon dioxide.
6 . The gas analyzing method according to claim 2 , wherein the sample gas contains at least one of a fluorine compound, a chlorine compound, and a bromine compound.
7 . The gas analyzing method according to claim 3 , wherein the sample gas contains at least one of a fluorine compound, a chlorine compound, and a bromine compound.