what is exact defination of puity and assay in hplc

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lakshminarayana
lakshminarayana's picture
what is exact defination of puity and assay in hplc

hai sir, please explain what exact defination of purity and assay .is there any varation between dried basis and anhydrous basis in assay calculation

Dr. Analytical
Dr. Analytical's picture
I think there are different

I think there are different definitions for each of these, but here are some common examples:

Purity refers to a single compound only, and is the percentage, by weight, of the actual compound.  The rest of the weight is impurities.  If the purity is greater than 99, a correction for purity is usually not required.

Assay can also refer to a single compound, having the same meaning as purity.  It also refers to the amount of an active ingredient in a pharmaceutical formulation.

Dry weight and anhydrous mean the same thing.  These are important values because the amount of water can change in some samples, which would affect the purity or assay values.  Reporting on a dry weight basis produces a consistent way to characterize a sample.
 

chintu
chintu's picture
 sir, i would like to know

 sir, i would like to know whether assay of a solution is to be considered when we have to calculate its normality and how?