Dear Tymur,

usually acids are used as presented by Gaudino et al. (2007): Article The role of different soil sample digestion methods on trace...

What about XFA? Article X‐ray fluorescence analysis of rocks, soils and sediments

Article Critical Comparison of Sample Preparation Methods for Major ...

BR

Nils

Dr. Tymur,

I hope you aware with "ASTM D 2974-87" method. This ASTM method widely used for determination of ash content in soil. After dry ashing of your soil sample you can choose the acid digestion methods to analyse your metal of interest with ICP-OES.

Regards,

In case of metal analysis in soil, there are several methods of soil treatment. but it appears to me that every methods have some sort of limitation. Since soil is a most heterogeneous system, it is very difficult to expect for a method that can give you 100% release of metals. For this reason, it is customary to mention the method of digestion of soil during reporting.All the methods mentioned above are also considered as standard methods and for this, I like to thank those Scientists/Profs.To my opinion, triple acid (HNO3,HCLO4 and HF) digestion of soil might be the best in comparison to any ashing methods.

Only digestion in a mixture of acids that includes HF, or fusion with a base, will give true 'total' elements. Otherwise the definition depends on the process, e.g. Fe recovered from a Kjeldahl digest (give method details).

If you are trying to understand anything about the behavior of nutrients or plants in the soil, total analyses are almost useless.

Why it is necessary the ashing of soil sample? For metal ions analysis can be used digestion.

Dry ashing- Heating samples placed in quartz crucible in muffle furnace

- Using microwave heating (use low heat initially to remove all the moisture then convert samples into ash using relatively high heat

Sulfated ashing- Volatile chlorides are converted to non-volatile sulfates

Closed system ashing

Low temp. ashing using plasma

Wet ashing- using sulfuric acid, nitric acid, nitric/perchloric acid, nitric/hydrogen peroxide, aqua regia.

High resolution--Inductivity coupled plasma-mass spectrometery

Generally ashing of soil is done by ignition followed by low and high temperature ashing. Low temperature ashing involve ignition (at 105-110 o C) followed by heated in furnace t 350-400 oC. And high temperature ashing involve ignition (at 105-110 o C) and ashing at 800-900 o C.

Actually, ashing of soil is done to convert all the metals present in soil as their oxide form and this oxide form is dissolved by treating with acid solution and volume make up is done to measure by using ICP-OES.

Try a microwave extraction and acid digestion method. (US EPA METHOD 3051A )

It can save time and solvent and suit for routine experiments.

important discussion, thanks for all

Ashing the soil sample in furnace that causes the metals to form their oxide. After that acid can be added prior to analysis.