now here's a fun topic. kinda wonder if they've got some magically easy methods now. seems like they can use mass spectrometry for literally EVERYTHING these days, even proteins and DNA and other macromolecules. just zap a sample somehow, sort out the gas-phase ions

but what about the other end, low-tech methods

like, I think you can estimate fats in foodstuffs simply by extraction with methylene chloride or similar