In summary, our discovery provides an effective method for fast
on-site halocarbon detection. In particular, the use of a
disposable test cartridge allows one to work on fast screening
in seconds. A camera flash can be used as a light source to
trigger the photochromic change. This provides a very
convenient qualitative test method for monitoring halocarbons
even on a field trip or for on-site screening. Quantitative
analysis can also be achieved using this method.