Čazo Čazim Mehmeti When I communicated with ALS Global I told them that I need chemical analysis expressed in the % oxide form. I sent them example of Neph. Sy. and everything was clear.
But, they make CA with Portable XRF instrument (pXRF). That means results can vary 5 - 20%(!?), and that range is if instrument is used correctly. That is for each element. Like for the copper, and for the oxygen. So, what is the error when they bond Cu and O together?
From portable XFR manual:
“Method precision is the amount the value of a data
point from a single measurement may deviate within a range due
to uncertainties in the analytical method in use. In pXRF analysis,
method precision may range from 5 to 20% when the instrument
is used correctly and a robust QAQC program is in place. This is on
par with exploration geochemistry and indicative methods, but it is
much poorer than that of the assay techniques used for financially
sensitive data (1.5 to 5%, or even less). This difference in precision
should always be taken into account when comparing pXRF results
to traditional assay results done on the same material. For example,
a letter of credit for a banking institution requires a definitive result,
such as 22.34% copper content, while pXRF results may be stated as
20% ± 5% copper content.”
Matthew Katz I send for ICP-ES. “Whole Rock Analysis”
