I am using XRF Horiba XGT 7200 (Kyoto, Japan) for assessing the levels of heavy metals in soil and plant samples. I got the results as mass %. Is there a way to convert the results in mg/Kg?
Dear Ali,
to my opinion your desired unit 'mg/kg' is a relative unit which means the amount of mass of one constituent relative to the mass of the whole compound. This is the same type of ratio as the mass% ratio.
For conversion:
1mg/kg= 10-3g/103g = 10-6g/g = 10-4*10-2g/g= 10-4mass%
Thus: 1mg/kg = 10-4mass%
and vice versa: 1mass% = 104 mg/kg
The calculations of Gerhard are right. However, I can’t apply it to the results.
Despite the output of the results is given as “Mass %”, the results could not be understood as % from the sample mass. Rather, I can understand it as % from the total mass of the elements in a sample. For example, the Mass (%) of one run for P, S, K, Ca, Cu and Zn are 8.01, 5.12, 49.69, 33.31, 0.95 and 2.91. The total mass (%) = 100. This means that K, for example, represents 49.67% of the total mass of the elements, not 49.6% from the sample mass.
My question is there a way to use these percentages to get the results as mg/kg
Yes Ali, I now see your dilemma.
Especially in plant samples there will be in addition C, N and O significantly contributing to the total mass of your sample. They do not really come up in XRF due to attenuation reasons.
But, sorry, at the moment I don't see a solution to scale the mass% of the series of your elements listed above to the mass% and thus to the mg/kg values with respect to the whole sample (all elements in the sample).
Maybe someone else will comment on that.
Hi Ali, I know this is a old question, but i will give my opinion
You can burn the sample first at 550 degC to get percentage inorganic and organic of your samples, so that based on the inorganic percentage you can calculate for the metals
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