I analyzed soil and ash samples using ICP-MS for 28 metals, then I resuspended those samples to collect PM2.5 particles in a filter using a selective inlet inlet. My only issue that Fe and Al from my filters are in the millions of ug/g. I could not find any thing in the literature compare to this result. I understand the filters will have higher results because the weight of the sample analyzed was less comparing to the soil and ash samples, but how I can explain this number.
Hello Modhi Alshammari , I'm surprised that you're surprised you got such typical results. According to http://www.fao.org/3/AC172E/AC172E03.htm which is a fairly general introductory page on soils, "Si Al and Fe are the three major cations in the soil". From what I understand in your question, you have taken an extract of the soil and resuspended some fraction which was then filtered. If you have removed all the soluble components, washing out the organic materials etc, then measuring these clay particles is going to give extremely high Fe and Al results.
You haven't told us how you extracted your samples, how much sample mass, how diluted the solution was and what the soil's composition was (clay sand or loam). You also haven't told us what your calibration range was or any details on the instrument settings. Or the digestion procedure including the extraction acids, heating profile, etc.
ICPMS is a very sensitive technique, which will give extremely high counts per second for any concentration over a few parts per million. If you have run an undiluted extract through the instrument, you could well have exceeded the calibration range and got nonsense results. You won't damage the instrument by running extremely dilute samples, so go for a 1 in 1 000 000 dilution and work back up to 1 in 1000.
While you're at it, check your filter materials for blank contamination. If that's where the anomaly occurred, then perhaps the filters or the housings you use are contaminated and causing high results.
Hello Mathew, I understand that Al, Fe, and Si are high in soil, but as you can see in the link you provided the % for Al were between 27 and 14% mine were 800%?
We extracted the sample using 50% nitric acid . The numbers were as follow, filter mass 0.000059g, digest 0.015L and dilution factor 10.32. Al result from the instrument 3132 ug/l. I am trying to find out the percentage of Al in my sample.
Thank you,
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