We are always been advertised to choose high purity or 100% purity of nootropics,but how can we identify the so called “highest purity”.When one batch of compound are produced and come out after the QA process,there will be one certificate of analysis.One the analysis there will be just data of sassy but not purity.
So what is the difference with nootropics purity and assay?
The verb assay means to “perform an examination on a chemical to determine how pure it is”. In our context, assay provides a metric that refers to the chemicals purity, usually expressed as a percent assay. On occasion it is also referred to as the purity of the chemical e.g. 99% or 99.9% pure. There is no test to determine the purity of a chemical so in practice the amount of impurities is quantitatively analyzed and the assay is determined by subtracting the sum of im-purities from 100, to infer the assay of the chemical. This leads to a Caveat Emptor or “Let the Buyer Beware” situation, since the supplier can choose to measure only certain impurities and if the customer does not know how the analysis is being performed, they will have no clue about the actual purity of the material.
Purity:It is calculated by area normalisation method, it can be directly find out by chromatograms obtained from HPLC.
% Purity = (Area of desired peak / Sum of area of all peaks) x 100
Assay:It is calculated against standard.
Calculation are given below
1) On as is basis = (Area of sample / Area of standard) x (conc. of standard / conc. of sample) x potency or assay of standard
2) On anhydrous basis = (Assay on as is basis / 100 – moisture) x 100
3) On dried basis = (Assay on as is basis / 100 – LOD) x 100
Potency:100 – (moisture or LOD + residual solvents + heavy metals + sulphated ash + impurities)
Normally you will see assay 98% HPLC or 99% HPLC,which are already very high quality.