Data
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