Hi

Is there someone who has troubles taking a homogeneous sample from a powder mixture? While taking different samples from the same powder mixture, we get results during analysis that are not reproducible. With the reference solution used to calculate the results there is no reproducibility problem.

I haven't had to deal with this sort of problem for years but when working at a prior company we had to sample powders with very nonuniform distribution of particles where one of the active ingredient was a small percentage of the total. In this case, we found it necessary to use special equipment specifically designed for sampling powders. There are probably lots of other companies that make such equipment but you can find a wide variety of powders samplers from Gilson Co. at http://www.globalgilson.com/index.asp

We deal in powdered detergents here which are historically non-uniform. We pulverize then use a riffler or riffle device to best prepare a more-uniform sample. Sometimes, one just needs to take a large sample size and then assay an aliquot.

Thank you both.