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Chemical Stability and Compatibility - Is scandium (Sc) a compatible internal standard for tungsten (W) analyses?

 
I noticed you you mentioned issues with compatibility of Sc with W. Why is this? We use Sc as our internal standard (final concentration 1 ppm) and analyze WO3 where the final concentration of W is about 80 ppm in 2% H2SO4 (v/v) and 1% HF (V/V). Should we look at a different internal standard for W analysis? Thank you for your help.
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Scandium (and all of the other rare earth elements) are known to form insoluble fluoride compounds that would reduce the amount of scandium dissolved in solution.  Low concentrations of Sc and HF are compatible, but there is still  a risk of precipitation that may affect the performance of your internal standard.  You could also have issues with such a precipitate clogging your nebulizer causing further problems with your analysis.  Refer to this link for reference from our interactive periodic table. https://www.inorganicventures.com/periodic-table In this case, since HF is absolutely required for the dissolution of tungsten, we would recommend a different element as an internal standard such as Indium, but many others may work.  You would need to confirm that you do not have a direct interference with the element you choose, as 80 ppm tungsten likely generates many unwanted interferences on the entire OES spectral range.  If you have any additional questions or concerns, please let us know.

Posted: 08/30/18 23:16:33

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