By removing a molecule of hydrogen from the THC – the researchers are inducing “oxidation” which then leads to a color change of the molecule because it changes the waveform of the molecule. The structure of THC includes a unit called a phenol. When chemists oxidize a phenol, the oxidation produces a member of a class of organic compounds called quinones. “We know how to oxidize a phenol into a quinone,” Garg said. THC and the quinone absorb light differently. With what happened then was that after the oxidation process occurred, the THC molecule was altered and produced a different color. While this is a very rudimentary way of detecting the presence of THC – it is very effective and requires very little tech or training to implement.