Would it not be possible to use 83Kr to check how much difference there is
between a gas blank and a ablation measurement? For Se isotopic measurements
with MC-ICP-MS indeed differences are found in the ArAr intensity blank vs
sample, but the Kr signal was so low that such an extra correction did not
change the values.
*Early Stage Researcher*
*Marie Curie Network AquaTRAIN*
*Department of Chemistry*
*University of Girona*
*Campus de Montiliv s/n*
*17071 Girona, Spain*.
2010/12/16 Don Chipley <[log in to unmask]>
> I have found, with high IP elements such as Kr, that the intensity
> of the
> Kr signal is lower during ablation, when the plasma is loaded, than it is
> in the gas blank. As a result, correction using the gas blank often over
> At 03:19 PM 12/15/2010 -0330, you wrote:
> >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.
> >Henry Longerich
> >Earth Sciences
> >Memorial University of Newfoundland
> >St. John's, NL A1B 3X5
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> Don Chipley Ph. 613 533-2183
> Queen's Facility for Isotope Research
> www.geol.queensu.ca/department/facilities + services/QFIR
> Dept. of Geol. Sci. Fax 613 533-6592
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