[kaliakon]

Hi everybody,

I operate a new Thermo ICP MS instrument.
I want to do elemental nutritional analysis for soils.
So, the extraction for K, Mg is done with ammonium acetate solution 1 N. Then I dilute the samples 200* in order to protect the instrument.
Moreover, I want to test the soils for micro elements, like Cu, Zn, Fe, Mn. The extraction that I have to use is:
1.967 g DTPA, 14.919 g TEA  and 1.470 g CaCl2 in 900 mL deionized
water. I have to adjust the pH to 7.3 ± 0.2 hydrochloric acid or hydrochloric acid solution and I bring the final volume to 1000 mL with deionized wate.
The maximum dilution that I can make is 50* because micro elements are in very low concetrations.

Has anyone done these kind of soil analysis with ICP-MS?
Do you believe that I will harm the detector of the instrument with the extaction salts?
Thank you for your time.

[Corribus]

ICP-MS does not tolerate solutions with high total dissolved solids (TDS). Generally you want TDS to be lower than 1%, and even much lower is preferred. If you have high TDS, you'll either want to dilute or use ICP-OES, which is more forgiving. Usually you will want your solution acidified as well. To be fair, we've run ICP-MS with TDS in the few percent range and it worked OK, but you may have to clean the instrument more frequently.

Thermo can probably help you develop a method if you are new to this.