And here we have the smoking gun (not taken through the checkpoint, of course) that our friend Ron lacks even a rudimentary education in basic chemistry.
Some things undergo a phase change from a liquid into a gas phase. Gasoline is one of these. Liquid gasoline can phase change into gasoline vapor (a particularly unscientific term) and what you end up with is gaseous gasoline. It is still a detectable long chain hydrocarbon - just in a gaseous state. Other things decompose into constituent molecules. One of these is hydrogen peroxide, or H2O2, which is a peroxide by virtue of having an oxygen-oxygen single bond. It is very unstable and rapidly decomposes into its components. When you uncap a bottle containing hydrogen peroxide, a chemical process of H2O2-->O2+H2O immediately begins. The H2O (that's water, Ron) retains its liquid phase and the O2 is offgassed. So to believe Ron, you must believe that there is some magic strip, known only to TSOs, than can detect oxygen in an oxygen rich atmosphere. Talk about false positives!
Now, to be complete,there is such a thing as hydrogen peroxide vapor, the manufacture of which requires special equipment, and which suffers from the unfortunate acronym of HPV. So that it wouldn't be mistaken for the virus that causes human ovarian cancer, its manufacturer, GEA Lyophil, trademarked it as VHP. In forensics, we use it sometimes as a "sterile" agent for disinfecting purposes. Since it has been classified as "Immediately Dangerous to Life or Health" in humans by the USCDC, it is not very readily available to the public. And it is not available at all in 100ml containers.
Since false positives have been mentioned, it is also important to note that every breath you exhale contains hydrogen peroxide. So while Ron is waving around his magic strip, everyone, including Ron, must stop breathing.