Actually, almost all even remotely-credible binary explosive components should alarm the ETD, as they involve heavily-nitrated compounds which should be part of the explosives detection profile. Many commercial and military binary liquid explosives utilize nitromethane, for example, as one component (which is poisonous and flammable without the other component, but not explosive); I'd wager the ETD would catch that in the same way it alarms on heavily-nitrated fertilizers on people's shoes from time to time, etc. Likewise, nitroglycerine (which isn't credible, but is still bandied about by media pundits as a candidate explosive) will alarm on glycerine and on the nitric acid, I believe.

You're probably thinking of TATP, which indeed doesn't alarm on either component, but as you said, is completely non-credible as an explosive formulated onboard a plane.