Hello everyone,

I am a new ICP-OES user, and trying to learn more about this instrument.

Can someone help explain how the "calculated concentration" is obtained?

I am asking because sometimes, there is a huge difference in method concentration and calculated concentration that lead to large error margin.

Thanks in advance.

It depends on the values that you have in the "weight", "volume", and "dilution" columns on the Sequence page. I'm assuming you have a 5110 ICPOES. Unadjusted concentration values are typically in ppm in the solution or ug/ml. This is then multiplied by the value for the sample in the "volume" column (ml), and divided by what is in the "weight" column (g). If there is a dilution factor, this value is multiplied by that factor. This results in an adjusted concentration in ppm in the original solid sample (ug/g). It also depends on the fit you have selected on the "Standards" page, whether linear, rational, or quadratic and whether you have selected weighted fit and whether you have forced through the blank or origin.