Hello Waqar,

that depends decisively on the sampling and the sample preparation. Your sample matrix also plays a decisive role. An example: You want to determine Fe(II) using IC in a water sample. Then it makes little sense to store the sample in a glass vessel. Fe(II) likes to form hydroxides. Therefore store the water sample in a plastic container (PE, PP) in which a small amount of HNO3 is present. You will then have acidic conditions and the formation of hydroxides is excluded. CO2 from the air can also form carbonate with e.g. calcium. Therefore fill the bottle to the rim. There must be no air in the container. Sampling and sample preparation account for approx. 80 % of the total error. You can't correct the mistakes you make here with analytics afterwards.

Regards

Markus

P.S.: Maybe you take a look here:

http://www.niordc.ir/uploads%5C86_106_Binder1.pdf

http://weppi.gtk.fi/publ/foregsatlas/article.php?id=3

Not likely! Nitrogen and Phosphorus concentrations are what are available to the plant. Thus, the extraction solution depend on the soil type.

Please consider soil as an ion exchanger... Scary? Not at all. Soil - depending on its composition (e.g., metal content) - has ion exchange capabilities. For this reason, the extraction solution should elute (displace) both anions and cations.

In older publications acidified (HNO3), KCl solutions were used addressing this very question.

I know, that there are several recipes to elute different type of soils, and my recommendation is to screen the literature, standards (ISO, and equivalent), etc. for respective information.

It might also be a good idea to look for guidance from colleagues from the geological departments of the university. They can tell you how to elute more acidic or less acidic soils...

Did you know that the Royal British Society evaluated the capability of soil to clean water, and protect groundwater (reducing ammonium etc) in the proximity of barns in the 19th century? They found the correlation but didn't know that it was due to ion exchange capabilities of soil...

Thank you everyone