James_Ball wrote:
It should be ok. The assay is telling you the purity of the standard material you are using, and that can be determined by many different methods, but if it is accurate it should carry over into other testing methods.
Using that purity you can also weigh up 1.046g of material to have exactly 1.000g of the pure substance, if that makes the later calculations easier to work with.
I should have emphasized that the HPLC assay of the analytical standard material was by area percent calculation at the given wavelength. Is it safe to assume that HPLC response factors are like Thermal Conductivity Detectors response factors, in that they are very similar across most compounds, such that the area is proportional to the weight in the area percent CofA HPLC value?
*My weight percent method however is run on a Flame Ionization Detector on the GC where area percent calculation can't accurately be used due wide variety of response factors based upon the number of carbon to hydrogen bonds per molecule. Thus, if I ran an area percent on GC FID the assay will be different than an HPLC area percent.
So bottom line is if HPLC analysis response factors are close to the same across the analyte and impurities, then that translates to actual weight on a balance of in my example of 0.956 grams of analyte?
**The main issue is that I know how much of the weight of the analytical standard material is due to the analyte for calibrating on the GC FID.