Properties of Carrier Gases for Gas Chromatography The following is a list of carrier gases sometimes used in gas chromatography, with properties relevant to the design of chromatographic systems. All data refer to normal atmospheric pressure (101.325 kPa). Mr: Molecular weight (relative molar mass) ρ25: Density at 25 °C in g/L λ: Thermal conductivity in mW/m °C η: Viscosity in µPa s (equal to 10-3 cP) cp: Specific heat at 25 °C in J/g °C
Gas Hydrogen Helium Argon Nitrogen Oxygen Carbon monoxide Carbon dioxide Sulfur hexafluoride Methane Ethane Ethylene Propane
8-140
Mr 2.016 4.003 39.95 28.01 32.00 28.01 44.01 146.05 16.04 30.07 28.05 44.10
ρ 25 g L-1 0.0824 0.1636 1.6329 1.1449 1.3080 1.1449 1.7989 5.9696 0.6556 1.2291 1.1465 1.8025
References 1. Lide, D. R., and Kehiaian, H. V., CRC Handbook of Thermophysical and Thermochemical Data, CRC Press, Boca Raton, FL, 1994. 2. Bruno, T. J., and Svoronos, P. D. N., CRC Handbook of Basic Tables for Chemical Analysis, CRC Press, Boca Raton, FL, 1989.
At 25 °C
λ mW/m °C 185.9 154.6 17.8 25.9 26.2 24.8 16.7 13.1 34.5 20.9 20.5 17.9
η µPa s 8.9 19.9 22.7 17.9 20.7 17.8 14.9 28.1 11.1 9.4 10.3 8.3
At 250 °C
λ mW/m °C 280 230 27.7 39.6 42.6 40.7 35.5 15.3 75.0 57.7 53.8 49.2
η µPa s 13.1 29.5 35.3 26.8 31.8 26.5 24.9 24.8 17.6 15.5 17.2 14.0
cp(25 °C) J/g °C 14.3 5.20 0.521 1.039 0.919 1.039 0.843 0.664 2.23 1.75 1.53 1.67
