We have currently set the ISTD Recovery % range to 80% to 120% on our ICP-MS. For some of our samples this range is exceeded. Should we dilute the sample and rerun it? Can we switch the ISTD to another that is within our 80% to 120% range, but maybe has an ionization potential that isn't as well matched? Can we use a wider ISTD Recovery range? What is the standard practice for this situation?