Is there a quantitative test/analysis technique that can determine if some chloroform has degraded into phosgene? Before I go to use any chemical that I've had in storage for a while, I try to check if it's degraded into something else (e.g.: checking the $\ce{H2O}$ content of $\ce{H2O2}$, checking for $\ce{H2O2}$ in $\ce{Et2O}$, etc.). This can usually be done using the appropriate test strip.

I have a 3/4 full bottle of chloroform that's been sitting on a shelf for about a year (probably less, actually), in an amber bottle to restrict the amount of light that can get to the chloroform. I'm aware that chloroform can break down into phosgene, and I know there are some ways to test for this, but I was hoping for a quick quantitative test that can be done without any hassle, but I can't seem to find anything out there. The Wikipedia page for chloroform states:


  Suspected samples can be tested for phosgene using filter paper (treated with 5% diphenylamine, 5% dimethylaminobenzaldehyde in ethanol, and then dried), which turns yellow in phosgene vapor.


I don't have either of the diphenylamine or the dimethylaminobenzaldehyde, and would prefer not to have to purchase them just for this simple test (I don't have any use for either chemical currently).
Does anyone know if there is a simple quantitative test that accomplishes the same thing? Preferably a test strip.
Not a quantitative test but a good proof of phosgene. You could use a pH paper strip. Chloroform should show a neutral pH, but if there is phosgene/HCl the paper will show acidity.