Rapid and Precise Analysis of Carbon Dioxide Clumped Isotopic Composition by Tunable Infrared Laser Differential Spectroscopy

Zhennan Wang, David D. Nelson, David L. Dettman, J. Barry McManus, Jay Quade, Katharine W. Huntington, Andrew J. Schauer, Saburo Sakai

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

The high precision measurement of doubly substituted ("clumped") isotopologues in CO2 is a topic of significant interest in isotope geochemistry. Here we describe the performance of a new isotope ratio laser spectrometer using tunable infrared laser differential absorption spectroscopy (TILDAS). The TILDAS instrument has two continuous-wave lasers to simultaneously measure the four isotopologues involved in the 12C16O2 + 13C16O18O ⇆ 13C16O2 + 12C16O18O exchange reaction. CO2 samples are trapped in a low volume (∼250 mL) optical multipass cell with a path length of 36 m. Each sample is compared to a reference gas, and clumped isotopologue precision of 0.01‰ (SE) is achieved within 20 min for 15 μmol samples. Similar precision is also achieved for bulk isotopic composition. The degree of rare isotope clumping in excess of strictly random distribution (Δ16O13C18O) measured by this TILDAS instrument varies linearly with theoretically calculated values and shows a very weak dependence on bulk isotopic composition.

Original languageEnglish (US)
Pages (from-to)2034-2042
Number of pages9
JournalAnalytical chemistry
Volume92
Issue number2
DOIs
StatePublished - Jan 21 2020

ASJC Scopus subject areas

  • Analytical Chemistry

Fingerprint Dive into the research topics of 'Rapid and Precise Analysis of Carbon Dioxide Clumped Isotopic Composition by Tunable Infrared Laser Differential Spectroscopy'. Together they form a unique fingerprint.

Cite this