Modified Carbon Nanotubes Decorated with ZIFs as New Immobilized Metal Ion Affinity Chromatography Platform for Enrichment of Phosphopeptides

摘要

ZIF-8, as one of the most representative zeolite imidazolate frameworks, is rarely used for the enrichment of phosphopep- tides due to its dissolution in acid solution. By introducing branched-chain polyethyleneimine (PEI), we have overcome the acid-intolerance shortcoming of ZIF-8 and applied it for phosphopeptides enrichment. A material with magnetic carbon nanotube (mCNT) as substrate, polydopamine (PDA) as hydro- philic interlayer and PEI-ZIF-8 as functional groups (denoted as mCNT@PDA@PEI-ZIF-8) was prepared through a facile method. The obtained material exhibited excellent performance on phosphopeptides enrichment, including high sensitivity (0.5 fmol), outstanding selectivity (molar ratio of β-casein: BSA=1:2000), reusability of at least 6 times and so on. The enrichment performance on complicated biological samples was also remarkable, 20 phosphopeptides were successfully detected from human saliva and 4 phosphopeptides from human serum, exhibiting its great potential and bright prospects in phosphopeptides enrichment.