First time users of the Finnigan MAT253 with the Kiel III Carbonate Device need to appreciate some inherant quirks of the hardware and software and how we have chosen to deal with those quirks. The MAT253 used to analyze your stable isotope samples uses two parallel CO2 extraction lines named "A" and "B" which acidify the carbonate at 70°C. As these lines are not identical, they produce slightly different numbers for standard data and thus we use different VPDB conversion values for each line. Unlike the earlier Kiel system, the Kiel III A and B lines do share a single capillary. When we analyze your data, we first send preliminary data. The preliminary data sent to you has been converted to VPDB with the most recent conversion numbers but should NOT be used for final publication. Please refer to the Post Processing section for further information concerning how we do the conversions. We will automatically send you the final data when it becomes available, usually 3-4 months following the preliminary data. We close datablocks when a piece of hardware changes (bellows, capillaries etc.). These blocks can be thousands of datapoints long and can be run over many months. We use all the NBS19 standards within each data block to produce a different VPDB conversion number for the A and B lines. The final data does not normally change by more than a couple of hundredths of a per mil and therefore will not change your analysis of the preliminary data or any figures you may make.

  • All of our data is reported in VPDB units. If you wish to report your data in SMOW units, please use the following equation:

    δSMOW = 1.03092 x δVPDB + 30.92

Data Evaluation