Does anyone know of a reference for a regulatory definition for the term 'Ambient' when used in HPLC? I've looked in the USP and all I can find is reference to using 'Ambient' when a temperature is not stated. What I'm looking for is a document which will have something along the lines of ' When using the term Ambient, this should be taken as XX degrees Celcius'.

Thanks.

It is my understanding that ambient is a term used when the normal range of temperatures found in the environment will not adversely affect the end results. For example "Dissolve with agitation at ambient temperature" would mean stir in the lab without cooling or heating. "Store in a sealed container at ambient temperature" means leaving it in a cupboard or on a shelf in the lab is acceptable. I have even seen sample collection instructions indicating that samples collected outside can be maintained at ambient temperature for transportation back to the lab. To me that means the samples are stable bewtween +/-40C. Basically ambient means to me that heating or cooling is not required and should possibly be avoided.

We have always taken ambient to be 17-27 degC. However, I guess it would depend on the "normal" temperatures in the country you're working in (Alaska is going to differ from New Mexico, for example)and wether you have decent Air Conditioning (that doesn't cause problems with fluctuating baselines, etc)!