Figure 1.

The distilling apparatus used to isolate CO₂ cryogenically from pressurized culture bottles after growth. Sample was introduced to the system through a needle. Liquid nitrogen collected CO₂ in a separate sample tube, allowing for subsequent removal of non-condensable gases by a vacuum. The auxiliary freezing coil was also cooled by liquid nitrogen and served as a secondary trap for assuring no CO₂ loss. Heating the auxiliary freezing coil after removing non-condensable gases allowed any trapped CO₂ to migrate to the sample tube.