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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
If you mean the analysis of chlorine gas in hydrocarbon based oil, then it is very difficult because the chlorine oxidizes the oil very quickly. In fact, there have been explosions caused by chlorine reacting with oil in valve packings.

If mineral oil has been exposed to small amounts of chlorine, the oil will go black very quickly due to oxidation. The chlorine will normally be converted to chloride.

A simple qualitative test you may consider is to wash the oil with DI water, slightly acidify the water with nitric acid if necessary, and add silver nitrate dropwise to the water and check for turbidity (silver chloride). Visible turbidity is normally seen at 3 ppm and higher chloride. If you need quantitative analysis, ion selective electrode analysis of the water wash is usually sufficient and is relatively inexpensive.

Ion chromatography is another more expensive, but higher performing method for analyzing chloride in the water wash.
Thanks fo all replies.

We want to look for Chlorine as from contamination from chlorine containing cleaning agens and similar.

Currently we want to do so in phosphate esters (firesafe hydraulic oils), and NH3 diluted mineral oil (refrig systems). We have methods for detecting chlorides in water (titration with silvernitrate), but are looking for direct analysis for Chlorine (Cl).

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