The CRDS-based Picarro G2201-i analyzer allows carbon stable isotope measurement in CH4 and CO2 without separation. The analyzer operates in one of three modes: 1) CO2 only, 2) CH4 only, and 3) CO2 and CH4 combined. In the combined mode, the measurement of CO2 and CH4 are interleaved every few seconds to produce a sampling rate that is faster than the gas turn-over time in the cavity. When the analyzer is in CO2 only mode or CH4 only mode, the precision improves, because more time is devoted to one molecule. In all modes, the analyzer precisely measures CO2, H2O and CH4 concentrations, with fewer calibration events than other spectral absorption-based instruments.
The analyzer is linked to the AutoMateFX sample preparation device, a front end system that prepares several types of samples automatically for a variety of types of analysis including carbon isotopes of carbonates, carbon isotopes of DIC, total calcium carbonate, total DIC, total CO2 in incubations. The AutoMate Prep Device acidifies solid carbonates and DIC in water, creating CO2.