Sequential purification of the released gas at each temperature step was first on titanium sponge during the process of temperature decreasing from 720 °C to 420 °C, and then on a SAES G50 getter at 450 °C to remove active gases and another SAES G50 getter at room temperature to adsorb hydrogen. The heavy noble gases (Ar, Kr and Xe) and the residual active gases were then adsorbed in a liquid nitrogen cooled charcoal trap before expanding into the cryogenic pump. Neon was trapped in cryogenic pump at 30 K, and was released at 70 K for measurements after helium was pumped away. The charcoal trap was set to room temperature to release trapped gases between every analytical running in order to renew the adsorption efficiency. Air standard delivered by a 0.1 mL pipette from the air tank was treated by the same purification procedure as the quartz did.