Electrochemical determination of rutin based on molecularly imprinted poly (ionic liquid) with ionic liquid-graphene as a sensitive element

摘要

A novel electrochemical sensor for rutin determination based on molecularly imprinted poly (ionic liquid) (MIPIL/ionic liquid-graphene (IL-GR) modified electrode was developed. MIPIL was synthesized via free radical polymerization using rutin as the template, 1-allyl-3-ethyl imidazolium bromide ([AEIm]Br) as the functional monomer and l,4-butanediyl-3,3'-bis-L-vinylimidazolium dibromide ([V_2C_4(mim)_2]Br_2) as the cross-linker. The composite of IL-GR as an electrode sensitive element was prepared using carboxymethyl-3-methylimidazolium chloride ([HO_2CMMIm]Cl) by one-step ultrasound method. Fourier transform infrared spectroscopy and scanning electron microscope were used to characterize IL-GR and MIPIL. The increased surface area and conductivity of IL-GR/GCE improved the sensitivity of rutin sensor. Under the optimum condition, good linearity for rutin analysis by the MIPIL-based sensor was obtained from 0.03 to 1 μM. A low limit of detection for rutin was 0.01 μM (S/N = 3). The MIPIL-based sensor demonstrated superiority on DPV response compared to the imprinted sensors based on traditional cross-linkers. The proposed sensor presented good selectivity for rutin and successfully applied for rutin determination in tablets with RSD of 3.05 % and the average recovery range was 98.3 %.