Polymeric ionic liquid functionalized MWCNTs as efficient electrochemical interface for biomolecules simultaneous determination

• Free radical polymerization of imidazole ionic liquid on MWCNT surfaces was realized.
• Efficient oxidation separation of AA, DA and UA with large current was achieved.
• Simultaneous determination with high sensitivity and selectivity was accomplished.
• The positive charge of imidazole groups was beneficial for the above performances.
• This work paves a new pathway way for functionalizing MWCNTs for practical analysis.

A thermal-initiation-free radical (polymeric ionic liquids (PIL)) reaction (multi-walled carbon nanotube (MWCNT)) was involved to form polymeric ionic liquids (PIL) layer on multi-walled carbon nanotube (MWCNT), which was designed as an efficient electrode modifier for simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA). The peak separation of AA–DA, DA–UA and AA–UA was 200 mV, 120 mV and 320 mV, respectively, accompanied by 5.9, 5.3 and 3.7 folds current for AA, DA and UA compared to the pristine-MWCNTs/GCE. The positive imidazole-functional groups along the PIL chains were supposed to be responsible for the oxidation separation of these biomolecules. Selectively and sensitively simultaneous determination of AA, DA and UA was successfully accomplished by differential pulse voltammetry, displaying a linear response from 3.0 to 1500 μM, 10.0 to 600 μM and 2.0 to 60 μM for each biomolecule with a detection limit (S/N = 3) of 1.65 μM, 2.01 μM and 0.46 μM, respectively. The present study not only provides functionalized MWCNTs with desirable interfacial performances, but also highlights the great potential of these functionalized tubular nanomaterials in the fields of electrocatalysis and sensing applications.

Figure optionsDownload as PowerPoint slide