Water Correction for iCO₂ Measurements Whitepaper

The Picarro G1101-i and G2101-i gas analyzers provide field measurements of the stable isotope ratio d¹³CO₂ with a precision of 0.3 permil in five minutes. In an isotope ratio mass spectrometry (IRMS) laboratory, it is customary to dry the samples to very low dew points (< - 45C) prior to isotope analysis. For field work, however, drying the samples is in many cases inconvenient or impractical. Water vapor can affect the reported delta via spectroscopic broadening or direct spectroscopic interference. In the G2101-i, the effects of the water vapor concentration, including its isotopes, has been characterized, and the reported isotope ratios have been corrected. Residual errors of less than 0.3 permil can be achieved in the G2101-i, even in very humid gas streams.

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G2131-i Isotope and Gas Concentration Analyzer

Measures δ¹³C for CO₂

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The Picarro G2131-i isotope and gas concentration analyzer enables measurement flexibility for a wide variety of applications—from atmospheric and ocean science research to food and beverage origin and authenticity. It can measure δ¹³C in carbon dioxide at less than 0.1 ⁰/₀₀ precision. It can measure carbon dioxide (CO₂) and methane (CH₄) gas concentrations, simultaneously, at 200 and 50 parts-per-billion (ppb), respectively. Water (H₂O) vapor is measured in parts-per-million (ppm) precision to correct and report CO₂ and CH₄ in dry mole fractions.

Measured δ¹³C in CO₂at >0.1 ⁰/₀₀ precision
Pair with peripherals to measure δ¹³C from many sample types
Simultaneously measure CO₂ and CH₄ gas concentrations
Measure H₂O vapor and report dry mole fractions

Accurate analysis of ¹³C-CO₂ /CO₂ is only possible if the influences of other molecules in the sample are quantified. The G2131-i analyzer makes precise measurements of CH4 and H₂O concentrations to allow the cross-influence of these species to be quantified and corrected. The analyzer comes equipped with ChemDetect™ software, a new layer of analysis that inspects the recorded spectra to find indications of contaminating species. The G2131-i analyzer can be paired with a variety of peripherals to extend and expand functionality.