Chromatography Forum

Dear members,
We need information or reference about standard treatment before using. For example:
Salicylic acid reference standard should be dried over silica gel for 3 hours before using.
Where could we get such information?
Should the sample powder be dried with the same method as standard?
Thank you.

Best regards,
Siswanto Tanuatmojo

syx:
You can put the standard compound into the desiccator and dry it under reduced pressure over night.
And by my opinion, to make the standard compoumd to constant weight is very important.

syx, your sample is a powdery mixture and you want to take an "aliquot" out of this powder (without prior dissolution of a definable quantity) for LC? That would be a no no? I would surmise that the inhomogeneity of your sample would likely be a larger source of error than its water content. Also, if you sold your sample powder with water in it, but analyzed it with the water removed....well.....
What I am trying to say: It depends on what you have to do.
Also, not all St and samples are hygroscopic.

Should the sample powder be dried with the same method as standard?

In short, No (unless your method tells you to - and I've never seen one that does).