Highly doubt this kind of equipment is present at the majority of institutions, or that it’s sensitive enough to find the trace of a trace amount like this. Sounds cool for a movie, though
Why? Prison contracts are big business. I've seen even small prisons with giant x-ray body scanners (the kind that were removed from airports, actually not those but more serious ones where you stand on a conveyor belt and your exposure is a full 3-5 seconds).
A mass spectrometer of the type they use at airports for explosives, can be used for drugs and easily acquired by any prison.
