Development of analytical method for the isotope purity of pure D 2 gas using high-precision magnetic sector mass spectrometer

Deuterium (D) is an isotope with one more neutron number than hydrogen (H). Heavy elements rarely change their chemical properties with little effect even if the number of neutrons increases, but low-mass elements change their vibration energy, diffusion rate, and reaction rate because the effect cannot be ignored, which is called an isotope effect. Recently, in the semiconductor and display industries, there is a trend to replace hydrogen gas (H2) with deuterium gas (D2) in order to improve process stability and product quality by using the isotope effect. In addition, as the demand for D2 in industries increases, domestic gas producers are making efforts to produce and supply D2 on their own. In the case of high purity D2, most of them are produced by electrolysis of heavy water (D2O), and among D2, hydrogen deuteride (HD) molecules are present as isotope impurities. Therefore, in order to maximize the isotope effect of hydrogen in the electronic industry, HD, which is an isotope impurity of D2 used in the process, should be small amount. To this end, purity analysis of D2 for industrial processing is essential. In this study, HD quantitative analysis of D2 for high purity D2 purity analysis was established and hydrogen isotope RM (Reference material) was developed. Since hydrogen isotopes are difficult to analyze with general gas analysis instrument, they were analyzed using a high-precision mass spectrometer (Gas/MS, Finnigan MAT271). High purity HD gas was injected into Gas/MS, sensitivity was determined by a signal according to pressure, and HD concentrations in two bottles of D2 were quantified using the corresponding sensitivity. The amount fraction of HD in each D2 was (4518 ± 275) μmol/mol, (2282 ± 144) μmol/mol. D2, which quantifies HD amount using the developed quantitative analysis method, will be manufactured with hydrogen isotope RM and distributed for quality management and maintenance of electronic industries and gas producers in the future.