Hello!

I am interested in quantifying some trace elements in calcite through LA-ICP-MS. I am using iolite4 software. I collected the elements of interest to me, and I collected 44Ca to use it as an internal standard. Since 44Ca is not the most common isotope, should I use its percentage (2.09%) and multiply it by the total Ca presence in calcite (40%), or should I just use 40% for the value in the internal standard?

In MACS-3 standard, there is only one entry for each element, so in a tutorial that I saw, the value of 40% was used. I do not understand why.

Many thanks

Faisal