Friend of mine looking for guide for preparation for standard solution. Two main topic should described:
1. what MAXIMUM dilution factor should be used (10x, 100x, 1000X) in preparation of working solution from stock solution ?
2. why using very small volumes of pipette (like 1 ul) can cause errors?

Above problems are relatively obvious, but I can not find any OFFICIAL document (FDA, EPA, ISO.???) describing it.

Thanks in advance!