Separation of chiral and achiral impurities in paroxetine hydrochloride in a single run using supercritical fluid chromatography with a polysaccharide stationary phase

•Chiral and achiral impurities of paroxetine were separated in 4.0 min by chiral SFC.•Chiral SFC is beneficial to separate compounds with highly similar structures.•Thermodynamic parameters were determined according to the van’t Hoff equation.•H-bonding and π–π interactions were main interactions between CSP and analytes.•0.005% impurities can be detected by proposed method.