The background electrolyte (BGE) composition has a pronounced effect on chiral separation in CE.In this article, we aimed to investigate the influence of the BGE composition on enantioseparation of binaphthyl derivative, where the atropisomers of 1,1-binaphthyl-2,2-diyl hydrogen phosphate (BNP) served as model compound and β-CD was used as chiral selector.It was found that SDS and β-CD exhibited competitive interaction with BNP, which was confirmed by the thermodynamic parameters obtained by CD modified CZE (CD-CZE) and MEKC (CD-MEKC) with the use of three different linear plotting methods.