Purity Threshold values

[tatiane Beatrice]

I have just started to work with peak purity on PDA detectors. I am working with Empower 3 and I am validating a method for Related substances whose results of purity angle are lower than purity threshold in a placebo contaminated with the impurities in the maximum concentration specified (like 0,005mg/ml) , however, the values of purity threshold for all substances I have obtained are 90.000. What does it mean?

[HPLC chemist]

The peak is impure. You should have 99.0 which is 99.0% pure.