Elimination of ghost peaks by optimization of anion exchange chromatography method for determination of gamma-carboxyglutamic acid (Gla)-domainless impurity in recombinant activated clotting factor VII drug products.

•Tris and Bis-Tris propane may interact with each other by aid of hydrogen bonds and create mega structures, this mega structures further may be absorbed to column positive functional groups and create ghost peaks.•Tris and Bis-Tris propane may not be suitable choices for some HPLC methods specially Anion Exchange Chromatography.•Increase mobile phase ionic strength by adding small amounts of NaCl in mobile Phase A can remove the ghost peaks.•Tris and Bis-Tris propane have synergistic effects on ghost peaks. This phenomena may also increase by using non HPLC grade water.