US Patent 7413550 - Bad breath detector using nanoparticles

http://www.freepatentsonline.com/7413550.html

This patent from Kimberly-Clark Worldwide teaches using silica or alumina nanoparticles in a high sensitivity bad breadth testing device. Claim 1 reads:

1. A breath testing device comprising nanoparticles and a visual indicating agent disposed on a substrate, wherein the visual indicating agent is color sensitive to at least one odorous compound present in the breath of a user, wherein the visual indicating agent is 4,4′-bis(dimethylamino)-benzhydrol.