Transient Response for Isotopic CO₂ Whitepaper

Stable isotope analysis relies on the simultaneous or near-simultaneous measurement of two individual species. In the case of the Picarro G1101-i and G2101-i gas analyzers, these two species are ¹²C¹⁶O₂ and ¹³C¹⁶O₂, which we denote ¹²C and ¹³C for simplicity. In the G1101-i, alternate measurements of ¹²C and ¹³C are made with a period of about eight seconds; the fact that the two gas measurements are not made simultaneously leads to systematic errors in the reported delta in certain conditions when the gas concentration is varying significantly. In this white paper, we report on improvements that we have made in the G2101-i to reduce these systematic errors by more than a factor of eight.

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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.