Listmembers,

Has anyone ever seen a calibration slope (known and measured values 
of two standards) deviate significantly from the expected 0.95 to 
1.05? We are consistently seeing 0.67.

This is a new Delta Advantage. d13C and d18O on a pair of OzTech CO2 
standards by dual inlet both have a slope of approximately 1, so the 
instrument is otherwise working fine (similar results by GasBench).

Hydrogen is a different story: a pair of OzTech standards by dual 
inlet has a consistent slope of 0.67, and SMOW/GISP/SLAP by H/Device 
shows similar results. H3 is consistently around 0.6, and the 
calibration performed on the H/Device seems stable enough that I 
could probably ignore the issue and run.

Any suggestions out there on how this could be?

Paul Eby


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