Preparation of Pure CO₂Standard Gas from Calcium Carbonate for Stable Isotope Analysis

Abstract

The isotope ratios of 13 C/ 12 C and 18 O/ 16 O for a sample in a mass spectrometer are measured relative to those of a pure CO 2 reference gas (i.e., laboratory working standard). Thus, the calibration of a laboratory working standard gas to the international isotope scales (Pee Dee Belemnite (PDB) for δ 13 C and Vienna Standard Mean Ocean Water (V-SMOW) for δ 18 O) is essential for comparisons between data sets obtained by other groups on