Question: how to calculate rrf for impurities?
Answer: Formula = [Slope of Impurity (known Impurity)/ Slope of Active] RRF value for Imatinib Impurity-F = [(Slope of Impurity-F)/( Slope of Imatinib)] = 61754.05/74167.65 = 0.83 RRF value for Imatinib Impurity-G = [(Slope of Impurity-G)/( Slope of Imatinib)] = 68661.27/74167.65 = 0.93 Page 6 Vol.4, No.4 (2011), 919-943 ...