[Analysis of hydrogen isotopes by gas chromatography using a MnCl₂ coated γ-Al₂O₃ capillary packed column]

The conventional packed column gas chromatographic analysis of hydrogen isotopes has low column efficiency, broad peak and long retention time. In this work, a γ-Al₂O₃ with MnCl₂ coated capillary packed column was tested at cryogenic temperature. The systematic column efficiency analysis and the hydrogen isotopes analytical technique research had been carried out. The results showed that, the γ-Al₂O₃ with MnCl₂ coating could greatly improve the surface degree of order, pore structure and adsorption properties. Also the o-H₂ peak and p-H₂ peak were eluted in a single area. The γ-Al₂O₃ with MnCl₂ coating was packed into a 0.53 mm inner diameter and 1.0 m long fused silica capillary column. It had a good linear relationship used this column with thermal conductivity detector (TCD) to detect the volume concentrations of hydrogen isotopes from 1 to 10 mL/L, and the relative error was less than 5% for low concentration sample testing. For H₂, HD and D₂, the retention times can be shortened to 39, 46 and 60 s, respectively. The limits of detection were reduced to 0.046, 0.067 and 0.072 mL/L, respectively. Compared with conventional packed column, capillary packed column had sharper peak form, higher separation degree of adjacent components, shorter retention time and lower detection limits. The above results indicate that the capillary packed column with TCD detector can be used for fast detection of low concentration of hydrogen isotopes and their online analysis.