The CHS converts carbonate samples to CO₂. It consists of an autosampler with a double hollow needle, which simultaneously flushes the sample vials with helium and collects the CO₂ resulting from the reaction of carbonate with phosphoric acid. After drying over phosphorus pentoxide, the gas is collected on a zeolite trap. By thermal desorption, this CO₂ can then be further graphitized in the AGE or directed via the GIS directly into the MICADAS. Controlled and optimal reaction conditions can be set in a heating block and up to 42 sample vials can be processed sequentially. In addition to solid samples, the CHS can also be used to study aqueous samples, for example, for dating dissolved inorganic carbon (DIC).