We are using peak purity (Purity angle and purity thresold) for demonstrating specificity (Interference and degradation) for analyte and impurity peaks. There is always an issue of peak purity failing for impurity and/or analyte peak, specifically in degradation. We have to process all of the injections with same processing method and it is very difficult to define max noise area for purity determination with no peaks in that area in all injections. Also, for peak purity the absorbance should be less than 1 AU. In all the related substances determination methods usually the absorbance is higher than 1 AU. Therefore, dilution is required. when you dilute sample, the impurity and degradant peaks disappear, so you have to consider peak purity of impurities in concentrated sample and analyte in diluted sample, which, we find time consuming and confusing.Is that any alternative to peak puirty determination. Anyone using methods/practices ohter than purity angle and purity thresold?