Reference Materials: Tin and Thallium Soil Extraction

Teresa has been doing some method development on Sn and Tl in soils. She noticed that her recovery on various CRMs is very low, having done both nitric acid and aquaregia preps. She hoped Paul might lend some information about tin and thallium extraction.

Dear Teresa,

It is likely you are dealing with soils containing the stannic (SnIV) and thallic Tl (III) oxides. These forms of these metals are very resistant to attack by any acid - even HF. Unfortunately, if you are looking for total Sn and Tl and not just 'extractable' Sn and Tl as per the acid extraction EPA methods, you must do the following:

  1. Fuse your sample with about a 20 to 1 ratio of sodium carbonate to soil at 1000 °C for about 15 minutes in a Pt crucible.
  2. Dissolve and dilute the sample fuseate using 1:1 HCl/water.

Take a look at our Interactive Periodic Table for compatibility and stability information for both thallium and tin.

I hope this helps. It's unfortunate that there are no acid extraction methods short of high-pressure (2000psi) nitric acid microwave digestions that would even stand a chance. Let me know if you have additional questions.

Serving you in chemistry,

Paul R. Gaines, Ph.D.
CEO of Inorganic Ventures & Fellow Chemist

DISCLAIMER: Advice offered by the chemists at Inorganic Ventures is intended for the individual posing the question. Feel free to contact us to verify whether these suggestions apply to your unique circumstances.