Preparation of a novel Zr4+-immobilized metal affinity membrane for selective adsorption of phosphoprotein

• Zr4+-immobilized metal affinity membrane (phosphate-Zr4+ IMAM) was prepared.
• The phosphate-Zr4+ IMAM exhibited selective adsorption towards phosphoproteins.
• The phosphate-Zr4+ IMAM exhibited good re-usability and re-productivity.
• The phosphate-Zr4+ IMAM was applied in the purification of real samples.

In this study, a novel phosphate-Zr4+ immobilized metal affinity membrane (IMAM) was prepared based on the surface initiated-atom transfer radical polymerization technique for the selective adsorption of phosphoprotein. The adsorption capacity and selectivity of the phosphate-Zr4+ IMAM were evaluated by using the mixture of standard phosphoproteins (β-casein, ovalbumin) and nonphosphoproteins (bovine serum albumin and lysozyme) as model samples. The adsorption isotherms and competitive adsorption results demonstrated that the phosphate-Zr4+ IMAM had higher binding capacity and selectivity for phosphoproteins over nonphosphoproteins. Moreover, the phosphate-Zr4+ IMAM exhibited good re-usability and re-productivity. Finally, the phosphate-Zr4+ IMAM was applied to separate phosphoprotein from real samples with high purity. Therefore, the as-prepared phosphate-Zr4+ IMAM could be a promising affinity material for the efficient enrichment of phosphoprotein from complex bio-samples.