yep, but that’s theirs. if you want to know what’s in your flask, have yours tested…
If your yield varies from 50-78% of crude, that could be a reflection on the potency of your crude just as much as a reflection of what you’ve got left in the flask.
the only way to know, is to test…
Which is why I’m a broken record recommending in-house analytics…
Edit: curious about how many questions in-house analytics can solve?
try Search results for 'in house analytics' - Future4200
Edit: @Beaker’s solution is certainly valid. Ideally you have a dedicated and calibrated bioassay team. see Organoleptics: In House QC?