Carbon Dioxide Isotope Analyzer Overview

Stable isotopes act as tracers for studying flows and fluxes of material through ecosystems and the atmosphere. In practice, scientists measure the stable carbon isotope content of air, plants and soil to quantify many phenomena including the recycling of carbon dioxide within forests, water use efficiency, partitioning ecosystem carbon exchange into its components, gross primary productivity and ecosystem respiration, and to identify and quantify the distribution and contributions of plant species to global productivity. In addition, stable isotopes of carbon may be used to determine the effectiveness of carbon sequestration strategies. For these studies, investigators require fast, accurate measurements over a wide range of carbon dioxide concentrations.

ABB LGR-ICOS Carbon Dioxide Isotope Analyzers exceed all of these requirements.

The new and improved model CCIA2-912 provides measurements of δ13C and δ18O as well as mole fractions (concentrations) of carbon dioxide and water vapor with high precision at measurement rates of up to 1 Hz.

ABB’s improved Carbon Dioxide Isotope Analyzer model CCIA2-912 incorporates a new fiber-coupled laser and provides many features that researchers need when measuring isotopic carbon dioxide, including:
 •  ultra-low drift and high precision
 •  ability to measure δ18O in CO2
 •  ability to measure water vapor in air
 •  δ13C and δ18O measurements for CO2 ranging from 300 to 25000 ppm
 •  Automatic determination of δ13C, δ18O and CO2 on dry mol basis

ABB's new CCIA3-913 provides measurements of δ13C, δ17O and δ18O, as well as mole fraction (concentration) of carbon dioxide, with extraordinary precision at measurement rates of up to 5 Hz.

In addition, LGR-ICOS Carbon Dioxide Isotope Analyzer is easy-to-use and requires low power to facilitate measurements in the field. The instrument provides accurate isotopic ratio measurements over an extremely wide range of CO2 values even when those values change rapidly.

These analyzers incorporate proprietary internal thermal control for ultra-stable measurements with unsurpassed precision, accuracy, stability and drift. Moreover, only LGR-ICOS analyzers provide reliable measurements (with guaranteed specs) at concentrations more than 20 times greater than typical ambient levels (to 25000 ppm carbon dioxide in air, for model CCIA2-912). Furthermore, LGR-ICOS analyzers report measurements over the widest range of ambient temperatures allowing users to easily record data in the field.

In addition, the availability of many value-added options and accessories extends the abilities of the unit to include measurements of discrete samples (collected in bags or vials, for example), to automatically handle multiple inlet sources (e.g., from flux towers or distributed sites for uninterrupted measurements over periods of weeks), and for measurements over an extended range of mole fractions.

The analyzer uses ABB’s patented Off-axis ICOS technology, the fourth-generation cavity enhanced absorption technique, which employs a high-finesse optical cavity as the measurement cell. ABB’s technology has many proven advantages over conventional first-generation cavity ringdown spectroscopy (CRDS) techniques. In brief, since the laser beam does not have to be resonantly coupled to the measurement cell (i.e. precise beam alignment is not critical), LGR-ICOS analyzers are relatively inexpensive, simple to build, and inherently robust thermally and mechanically. In addition, since ABB’s technology can record reliable absorption spectra over a far wider range of optical depths (absorbance values) compared with CRDS, LGR-ICOS analyzers provide measurements over a much wider range of mole fractions (gas concentrations). Finally, due to the ease and simplicity of recording and quantifying the measured spectra using ABB’s Off-Axis ICOS, LGR-ICOS analyzers display the entire absorption spectra to the user in real time allowing for immediate system diagnostics and performance validation.

All LGR-ICOS analyzers have an internal computer (Linux OS) that can store data practically indefinitely on its hard disk drive and send real-time data to a data logger via the digital (RS232) and Ethernet outputs. Furthermore, the Carbon Dioxide Isotope Analyzer may be controlled remotely via the Internet. This capability allows the user to operate the Analyzer using a web browser practically anywhere. This remote access allows full control of the instrument and provides the opportunity to obtain and share data, and to diagnose instrument operation without being on site.