View of the automated vacuum line for processing samples for the triple isotope composition of O2 from left (top) and from right (bottom). Gas samples (flasks in cold bath, far right of lower figure) are passed through a cold trap and collected on mol sieve at liquid N2 temperature. The mole sieve is then heated and noncondensible gases are desorbed into a helium stream that passes through a gas chromatograph (far right, top picture). O2 and Ar coelute and are trapped on mole sieve at liquid N2 temperature. These gases are condensed in tubes cooled by a helium refrigerator to 15 K. These tubes, are mounted on a cart that is then wheeled into the mass spec lab for analysis. 6-10 samples and/or standards are processed under computer control.