Titrating ASA Tablets: NaHO and Ethanol

[appykid]

How do I find the quantity of active ingredient in a commercial ASA tablet, using titration and NaHO? I think that I'm supposed to use ethanol too.

 

[chemisttree]

When I did that test back in the day, we used iron to complex with the stuff and measured the intensity of the Fe complex. You could use NaOH in theory but you will need to get the whole tablet to dissolve to accurately analyze it. Ethanol should work but I'm not sure.

We hydrolyzed the acetylsalicyclic acid with excess NaOH to salicylate and then adjusted the pH to neutral and added the Fe to generate the purple complex. I remember using a Spec 20 for the analysis.