[doof]

i have a method for acid hydrolysis of of an amino acid in a protein. the sample is heated at 110 degrees C for 20hrs in hydrolysis tubes. im just wondering if hydrolysis tubes are necessary. what do they do? how do they work? can i just heat the sample in any plastic tube/glass beaker etc?

[orgopete]

As I note from the procedure described, the temperature is above the atmospheric temperature for water, therefore the hydrolysis tubes are pressure vessels. If you were to do the hydrolysis at one atmosphere, then you need to double the reaction time.

I don't know the stability of different plastics at different conditions. You cannot use nylon as it is a polyamide and would hydrolyze. Other plastics may be not hydrolyze, but could distort over time, so glass would seem more stable.

[cpncoop]

If you're using conc. HCl as the solvent, it boils at 109, so you don't need pressure.  I guess it all depends on the acid being used.  Glass should be fine to use - avoid steel, and most plastics due to the temp (PTFE or teflon would be fine).

[orgopete]

Oops, righto. I didn't think about the effect on the boiling point. So it could be 6M HCl or constant boiling HCl.

I still think that 100°C for 20 hours should not be done in a open vessel. You could use a flask with a reflux condenser or simply heat it at reflux for 20 hrs. I was thinking that the procedure was the equivalent of that by heating in a sealed vessel. In that case, I presumed there was some pressure though not as much as I incorrectly expected.