# How to account for dilution in the sample solution when reading calibration standards?

I have been provided the following table of calibration standards from an ICP-MS experiment. (Some text is in German, I am operating in a location where DIN standardization is ubiquitous)

I understand that I must subtract the provided method blank from each of the provided data points before plotting them and drawing a regression line, but the sample solution I am working with (500 mg manganese slag in 10mL of a mixture of hydrogen peroxide and nitric acid) has also been diluted in a 1:10 ratio with water. How do I account for this dilution when calculating the mass concentration of manganese of the sample?

There is a very simple dilution formula:

C$$_{initial}$$ x V$$_{initial}$$=C$$_{final}$$ x V$$_{final}$$

where C and V refer to concentration and volume in consistent units.

When you analyze the sample (=Probe in your table) using the regression equation, the concentration unit of the sample will be the same as your standards ng/mL.

Lets say your diluted sample conc. from the regression equation 12 ng/mL (= C$$_{final}$$ see the above equation), all the variables are known to you except C$$_{initial}$$. You know the sample volume (=V$$_{final}$$), you must also know how much initial volume was used for dilution.

Once you find C$$_{initial}$$, one can determine the mass from the original sample volume, because analyte mass, Mn = concentration x volume.

Note: In certain methods multiple dilutions are made, then one must apply the dilution formula repeatedly for each dilution.

• Thanks for pointing out that multiple dilutions could happen. In this case it was just the one, however. Jun 17, 2021 at 15:17