Hi maybe you could evaporate  the organic solvent since the acid seems to have a very high boiling point  (460°C at atmospheric pressure) then add a very small amount of water to dissolve the acid and in this way the rubber would be separated too. Then you can try to titrate the acid dissolved in water or perform UV-Vis or HPLC. If the water is too much you can also evaporate some of it to concentrate the acid. I hope this helps.

Hi Maria, thanks for your response.  I tried something similar already (pre-concentration), but had some issues separating the rubber from the acid afterwards.  I still needed to use organic solvent to take up the acid/rubber mix and titrate under non-aqueous conditions.  There is literature out that suggest performing titration in benzene, but this is really something I would like to try and avoid.  I was more thinking along the lines of chromatographic approach now as well

Acid-base titration seems a feasible method for the volumetric analysis of camphor-10-sulphonic acid (CSA) dissolved in ethyl acetate (EtOAc), even considering that its practical application may be not straightforward. CSA could be partially extracted to aq. phase, by adding either water or a pH-neutral brine ─ NaCl or CaCl2 aq. sol. ─ to the EtOAc solution. Use of brine could possibly be considered, to further enhance immiscibility, due to the salting-out effect. Chloroform could also be used, to further extract residual EtOAc from aq. phase. Repeated aq. extractions should be able to quantitatively extract most of the acid. The extracted aq. phase, containing CSA, can be titrated with a standardized aq. sol. of NaOH or KOH, being sodium (or potassium) 10-camphorsulfonate formed. A minor contribution from CSA could possibly remain dissolved in the EtOAc phase, even after repeated extractions with water or brine. Some degree of inaccuracy could therefore result, as the measured CSA concentration could be somewhat lower than the actual concentration. Another possible source of error relates with EtOAc dissolved at the aqueous solution, since it would be hydrolysed by the added alkali during titration. Calibration of the proposed titration method with a set of standard solutions of CSA dissolved in EtOAc would help to limit these possible sources of error.

Thanks Carlos, will give it a go

Once you are able to extract CSA, then you can think of making a Methyl Ester of the same and can then it can be analyzed easily by Gas Chromatography using a polar capillary column.

Good suggestion Girijan