Now think about research on chemicals, everybody has a different source, different quality control (most academic labs do 0 qc on incoming chemicals). I have bought chemicals from major and minor vendors and I could tell you all kind of horror stories... Wrong molecule, inert powders added to increase weight, highly toxic impurities... Now you add that to assays and academics that have been optimized for years to scream "I HAVE A NEW DRUG AGAINST X" anytime they stare too long at the test tube...
This is absolute baloney. I've ordered numerous research grade chemicals from multiple suppliers and not once has any of them been the wrong one nor outside of stated purity grade — and I regularly checked, since it's standard practice. If a solid organic material is in a lower grade of purity it is typically recrystallized.
Now, yes, impurities — even minor ones — can have significant effects. But that tends to be in rare circumstances and chemists are quite aware of the need to check for it where it's most needed such as catalysis research.
No one is going to scream "I have a new drug" for something for which the composition is unclear.
I don't know what world you live in, but it isn't one of a typical North American nor European university research lab.
This was my work to check for quality of chemicals entering the lab. NMR, MS, IR... And over 15 years I have seen dozens and dozens of cases. Now most labs call HPLC with UV sufficient for quality analysis. Lots of things looked "fine" that way that's for sure. Note that I was in the drug discovery world not in the inorganic chemistry world where things are ususally of much better quality.
