I once worked in labs where we had to take samples of powders. There is a method of deviding
I completely agree with all of the above as I was trained to do the same i.e. sub-sample powders.
I used to regularly sub-sample ground rock powder for analysis. Obviously we went to a lot of trouble to test our methods as being statistically viable. The key element was to endure (oops 'ensure', though 'endure' is not a bad description!) thorough mixing. This was reasonably reliable with rock powders ground to a common particle size, though the mass differences in the minerals did cause separation over time if just left on the shelf. It is the thorough mixing which is the problem - the splitting is easy enough. (I'll happily discuss this off-thread).
The reason I would not advocate splitting powders in this case is that it is not necessary. A couple of gallons of stock solution is not that big a problem.
I completely agree with all of the above as I was trained to do the same i.e. sub-sample powders.

