A method of separating a bispecific antibody comprising an Fc domain from a solution comprising said bispecific antibody, said method comprising (a) contacting said solution with a hydroxyapatite chromatography medium, wherein said solution further comprises (i) one or more fragments of said bispecific antibody, which one or more fragments comprise an Fc domain; and/or (ii) one or more bispecific antibody specific byproducts (BASBs) having a heterodimer or homodimer of antibody heavy chains, a single antibody light chain and a Fab or scFab fragment, which one or more BASBs comprise an Fc domain; (b) adsorbing said bispecific antibodies to said hydroxyapatite chromatography medium, and (c) eluting said bispecific antibody from said hydroxyapatite chromatography medium in the presence of chloride ions, wherein said eluting comprises, (i) a starting composition of the elution buffer having a pH of 6.5 to 8.0, a phosphate ion concentration of between 1 mM and 20 mM, a calcium ion concentration of between 0.01 mM and 0.5 mM and a chloride ion concentration of between 10 mM and 200 mM; (ii) increasing the chloride ion concentration of said starting composition according to a gradient; and (iii) obtaining an eluate fraction, which fraction contains said bispecific antibody but does not contain at least one of said one or more fragments and/or does not contain at least one of said one or more BASBs (a) contacting said solution with a hydroxyapatite chromatography medium, wherein said solution further comprises (i) one or more fragments of said bispecific antibody, which one or more fragments comprise an Fc domain; and/or (ii) one or more bispecific antibody specific byproducts (BASBs) having a heterodimer or homodimer of antibody heavy chains, a single antibody light chain and a Fab or scFab fragment, which one or more BASBs comprise an Fc domain; (i) one or more fragments of said bispecific antibody, which one or more fragments comprise an Fc domain; and/or (ii) one or more bispecific antibody specific byproducts (BASBs) having a heterodimer or homodimer of antibody heavy chains, a single antibody light chain and a Fab or scFab fragment, which one or more BASBs comprise an Fc domain; (b) adsorbing said bispecific antibodies to said hydroxyapatite chromatography medium, and (c) eluting said bispecific antibody from said hydroxyapatite chromatography medium in the presence of chloride ions, wherein said eluting comprises, (i) a starting composition of the elution buffer having a pH of 6.5 to 8.0, a phosphate ion concentration of between 1 mM and 20 mM, a calcium ion concentration of between 0.01 mM and 0.5 mM and a chloride ion concentration of between 10 mM and 200 mM; (ii) increasing the chloride ion concentration of said starting composition according to a gradient; and (iii) obtaining an eluate fraction, which fraction contains said bispecific antibody but does not contain at least one of said one or more fragments and/or does not contain at least one of said one or more BASBs (i) a starting composition of the elution buffer having a pH of 6.5 to 8.0, a phosphate ion concentration of between 1 mM and 20 mM, a calcium ion concentration of between 0.01 mM and 0.5 mM and a chloride ion concentration of between 10 mM and 200 mM; (ii) increasing the chloride ion concentration of said starting composition according to a gradient; and (iii) obtaining an eluate fraction, which fraction contains said bispecific antibody but does not contain at least one of said one or more fragments and/or does not contain at least one of said one or more BASBs <EOS>