There are devices which can look at the chemical composition of a liquid inside a bottle and actually find the presence and amounts of specific chemicals. These devices are used in lab settings and have been available for years before the war on liquids started.

They are not expensive, easy to deploy and the technology could be added to an existing carry-on scanner - no sample prep necessary, all you need to do is drop your bottles in a bin so the scanner has a clear view of them and you're done.

The TSA has shown gross imcompetence by not even testing such a device because it's easier for them to just say "no liquids allowed!" than it is for them to actually do something to mitigate the threat.