On 16/12/2010 1:43 PM, Gauthier Gilles wrote:
> Dear List,
> When you suggest La-ICP-MS for Sr isotopes are you not worried about serious Krypton Interferences?
While Kr is often treated as an interference, due to the history of
Thermal Ionisation MS methods, Kr is better treated as a background
subtracted with the "gas background" which is taken before every analyte
ablation with the laser not firing on the sample. This gives new Kr
values for every ablation. And avoids the error from inaccurate mass
bias (mass discrimination) values for Kr.
I wish to define a background as the signal present in the absence of
the analyte (for Sr both Kr and amplifier offset and continuum signal).
An interference is due to the presence of other elements in the sample
(for Sr doubly charged REE and/or Ca dimers or CaAr ions), but which
does not produce a signal when the interfering element is absent.
Memorial University of Newfoundland
St. John's, NL A1B 3X5