Determination of methane-D4 and ethane-D6 in ethylene-D4 by gas chromatography

Deuterated ethylene-D4 is a special molecule formed by replacing the hydrogen atom-1H on the molecule with deuterium atom-D. It has more stable properties and can significantly improve the chemical stability of the corresponding site. The special properties of ethylene-D4 make it have important applications in fields such as healthcare, military manufacturing, aerospace, and aviation. With the continuous development of science and technology, the application of ethylene-D4 is becoming more and more extensive, and the quality requirements for ethylene-D4 products are also increasing. Deuterated methane-D4and deuterated ethane-D6 are the main deuterated impurities in ethylene-D4 products, and their concentration seriously affects the quality of ethylene-D4 products. Therefore, it is necessary to study a detection method to meet the requirements. A method was developed for the determination of methane-D4 and ethane-D6 impurities in ethylene-D4 products by gas chromatograph, using gas valve injection and alumina (deactivated by sodium sulfate) capillary column. Through the selection of chromatographic column, the optimization of shitter ratio and column flow instrument conditions, the peak order of the compound is changed to avoid the interference of the principal component on the impurity detection. The qualitative and quantitative analysis is carried out under the hydrogen flame ionization detector. By using the external standard method, record the peak areas of each component and directly calculate the content of the compound. Methane-D4 and ethane-D6 compounds have good linearity in the range of 0.0020 % ~1.00 %, and the correlation coefficient (R2) is greater than 0.995. The method detection limits of the two components were 0.0003% and 0.0002%, and the recoveries were 97.1% ~106.1% and 97.3% ~104.7%, precision range between 1.95%~ 3.73% and 1.65%~2.98%. The established method was applied for actual sample detection, the three components of deuterated ethylene, deuterated methane, and deuterated ethane were completely separated. All types of components have good peak shapes and high responses, and the air component in the sample does not interfere with the target component. The method established by the research has the characteristics of simple operation, low detection limit, high accuracy, and good reproducibility, which meets the detection requirements of methane-D4 and ethane-D6 in ethylene-D4 products.