Single-walled carbon nanotubes as stationary phase in gas chromatographic separation and determination of argon, carbon dioxide and hydrogen Original Research Article

A chromatographic technique is introduced based on single-walled carbon nanotubes (SWCNTs) as stationary phase for separation of Ar, CO2 and H2 at parts per million (ppm) levels. The efficiency of SWCNTs was compared with solid materials such as molecular sieve, charcoal, multi-walled carbon nanotubes and carbon nanofibers. The morphology of SWCNTs was optimized for maximum adsorption of H2, CO2 and Ar and minimum adsorption of gases such as N2, O2, CO and H2O vapour. To control temperature of the gas chromatography column, peltier cooler was used. Mixtures of Ar, CO2 and H2 were separated according to column temperature program. Relative standard deviation for nine replicate analyses of 0.2 mL H2 containing 10 μL of each Ar or CO2 was 2.5% for Ar, 2.8% for CO2 and 3.6% for H2. The interfering effects of CO, and O2 were investigated. Working ranges were evaluated as 40–600 ppm for Ar, 30–850 ppm for CO2 and 10–1200 ppm for H2. Significant sensitivity, small relative standard deviation (RSD) and acceptable limit of detection (LOD) were obtained for each analyte, showing capability of SWCNTs for gas separation and determination processes. Finally, the method was used to evaluate the contents of CO2 in air sample.