Yesterday, I mentioned naphthoresorcinol as a reagent for aldehyde testing. Did you know: at one point during the Cold War, the Soviets used to put a certain aldehyde on American operatives in the USSR as a tracer?
That aldehyde, NPPD, caused a kerfuffle in the 80’s. There was outrage that Americans were being “tagged,” and speculation as to whether it might be dangerous. Some analytical chemists leaned back, scratched their beards, and said “sounds kind of neat.” And even recently, the compound was re-examined.
Anyone have any NPPD stories?