using a combination of test kits you could find:
PMA, DXM , MDA from MDMA/MDEA, ampehatmines, some phenethylamines (2-cb, DOB, DOM)
and PCP should come up as a Ketamine-like substance on E2 - mandelin test.
epehdrine is easy to test for, if it comes up negative on e1 - marquis, tastes bitter and does fuck all.
So we are pretty much there.
They need a tester that tests for one substance only so you can pick up drug combos.
Like:
MDxx test, then one for PMA.....etc