Sciencemadness Discussion Board

determing % in CH2O solution?

Justin - 5-11-2010 at 10:06

Hi, i recently recieved some formalin USP solution from a scientific supplier, it doesn't list a % but im guessing its the usual 37%. But to be sure i want to titrate it. Is there any specific reagent/method to do this?

Thanks, Justin

unionised - 5-11-2010 at 10:19

There are a number of approaches. In my experience the iodimetric one is better than the one based on hydroxylamine.
Have a look at this one.

http://motion.kodak.com/motion/uploadedFiles/US_plugins_acro...
as an example.

If you need great accuracy and precision then the best bet is the gravimetric determination based on reduction of silver oxide in t butylamine to silver.
Don't bother with this one unless you need the result to 4 digits or more.

smuv - 5-11-2010 at 18:15

The msds must say. Formaldehyde must be listed because it is toxic/carcinogenic.

Justin - 5-11-2010 at 21:18

I purchased it from elemental scientific, they don't have a link to any msds's on their site, i might just have to email them. Its just listed as "formaldehyde USP, solution" on the site and the bottle.

smuv - 5-11-2010 at 21:33

If you don't want to titrate. I would assume it to be a 37% formalin solution. Do a websearch, of usp formalin, it essentially confirms this.