Interaction between bilirubin and sodium deoxycholate and their adsorption from mixed solutions on the surface of silica sorbents

The interaction between the bile pigment bilirubin and sodium deoxycholate is studied in aqueous buffer solutions at pH 7.4. It is established that bilirubin forms strong complexes with deoxycholate trimers. The complexation constant is determined by spectrophotometry. The adsorption of bilirubin and sodium deoxycholate from their mixed solutions on the surface of a hydrophilic and two hydrophobic silica sorbents is investigated. It is shown that bilirubin is adsorbed on the surface of all these sorbents only in the free state. Sodium deoxycholate is adsorbed in the forms of monomers and trimers. The affinity of all adsorbed particles is higher for hydrophobic silica sorbents. The binding constants of bilirubin, as well as monomers and trimers of deoxycholate, with the surfaces of all examined sorbents are determined.