Hi Mr Hughes
Mr Joe Ban is a chemical engineer we work with from J&M,
I asked him the question and he said;
"There is at least 3 ways to identify Cl atoms.
1. One is Infra Red, where the C-Cl atom bond has specific wavelength in IR spectra.
The IR spectra will also show different wavelengths for C-Cl , C- 2 Cl and C- 3 Cl bonds.
2. Chemical Oxidation, and collection of vapour by alkaline absorbent, and subsequent analysis by wet chemistry.
3 Fusion of materials with alkali salts to decompose organics, and capture Chlorine or Chloride into alkaline salts, and wet analysis carried out on dissolved ignition residue.
Infra red cannot see Sodium or Potassium Chloride as these are transparent to IR spectra analysis.
Other metal Chlorides may react with IR, but the person interested in analysis needs to consult an IR spectra handbook, where various bonds for Cl may be available that can be identified by IR analysis.
Regards RobS