Yes thank you Azharul. I agree and can add orbital grinders with ceramic working surfaces. However no lab that tests thousands of samples a year would thank me for such recommendations, Paul.

Hi there

I have used Fastprep 24 with glass beads.

Unfortunately is only for small samples and have to take the supernatant fast to avoid the glass from binding any metals

Thanks Leonado

The only manufacturer who proposed some kind of grinders for such application is IKA though frankly speaking I cannot remember the model.

According to my experience please believe: use a common coffee mill. It is very unlikely the abrasivity of plants is high enough to cause contamination from mill grinding set. Anyway if you are lucky you will find a coffee mill with non-stainless steel grinding set that less contains Cr, Ni and Mo and which milling contamination can be easily removed by simple magnet.

Thank you Sergey. Plain old fashioned steel and a magnet may indeed be a solution. I was wondering if a (small) manufacturer may have anticipated the problem by going to tungsten working surfaces. The reason for the question is that I'm trying to get some information together ahead of a planned interlaboratory study in anticipation of the outcome.

You are welcome, Paul.

You see, today limits of elements those should be determined in plants (to be used in food for instance) are quite high in comparison with possible mill level even with stainless steel grinding set.

It means nobody will buy expensive tungsten carbide - general use does not expect any problem and does not require changes. Also tungsten carbide grinding set is usually doped with cobalt - so you will get this milling contamination in planetary type mills.

As for some kind of coffee mill with tungsten carbide grinding set - I'm afraid it is technically impossible due to characteristics of this material.

Agreed Sergey thank you. Happy Christmas, Paul.