Polymerized ionic liquid-multiwalled carbon nanotubes composite for the separation of serum albumin

Polymerized ionic liquid (PIL), poly(1-vinyl-3-ethylimidazolium bromide) (poly(ViEtIm + Br - )), is synthesized and it is immobilized onto the surface of multi-walled carbon nanotubes (MWNTs) via π-π stacking, giving rise to a PIL-MWNTs composite. 15 mg of the composite is packed into a mini-column for the on-line isolation/purification of bovine serum album (BSA) in a sequential injection system. A 91% adsorption of BSA in 2 mL solution (50 μg mL -1 , pH 5.2) is achieved. The retained BSA can afterwards be quantitatively recovered with 0.04 mol L -1 citrate buffer. The entire isolation process takes 500 s giving rise to an enrichment factor of 5. The practical applicability of this on-line protocol is demonstrated by processing human whole blood for the isolation of human serum album, and satisfactory results are obtained by assay with SDS-PAGE.