Layer-by-layer assembly sensitive electrochemical sensor for selectively probing l-histidine based on molecular imprinting sol–gel at functionalized indium tin oxide electrode

A novel sensitive and selective imprinted electrochemical sensor was successfully constructed for the direct detection of l-histidine by combination of a molecular imprinting film and multi-walled carbon nanotubes (MWNTs). The sensor was fabricated onto an indium tin oxide (ITO) electrode via stepwise modification of MWNTs and a thin film of molecularly imprinted polymers (MIPs) via sol–gel technology. The introduced MWNTs exhibited noticeable enhancement on the sensitivity of the MIPs sensor. Meanwhile, the molecularly imprinted film displayed high sensitivity and excellent selectivity for the target molecule l-histidine. The proposed imprinted sensor was characterized by using scanning electron microscope (SEM) and electrochemical methods involving cyclic voltammetry (CV), differential pulse voltammetry (DPV) and amperometric i–t curve. A linear ranging from 2.0 μmol L−1 to 1.0 mmol L−1 for the detection of l-histidine was observed with the detection limit of 5.8 × 10−9 mol L−1 for S/N = 3. This imprinted electrochemical sensor was successfully employed to detect l-histidine in human blood serum.