Molarity for Glycerol? - silly question? (Feb/17/2010 )
Hi...i'm am planning to perform a glycerol dehydrogenase assay and the protocol i am looking at is looking for a final concentration of 500mM glycerol. We have a bottle of glycerol in the lab
The question is is the bottle of glycerol already a 1M? I mean you can do the v/v thing but i guess i'm confused about it all...
Unless it says 1M on the bottle, it is unlikely to be 1M. Pure glycerol is a colourless, viscous liquid and quite dense. You should be able to calculate the number of moles in a given volume of a pure liquid using the volume, density, mass and molar mass. volume x density = mass, n=mass x molar mass
Given the viscosity of glycerol, it is much more accurate, typically, to weigh a specific amount rather than to attempt to pipet it.
I would weigh an amount of glycerol in a bottle and then bring it to the correct volume with water. You don't need to know the density to do this.