Nickel hydroxide nanocrystals-modified glassy carbon electrodes for sensitive l-histidine detection

Hourglass-like nickel hydroxide nanostructure was synthesized via a simple and facile route in solution. The as-prepared nickel hydroxide nanocrystals were characterized by X-ray diffraction (XRD), scanning electronmicroscope (SEM) and transmission electron microscopy (TEM) for the morphology study. The TEM experimental data indicate that the growth of hourglass-like nanocrystal is along the c axis of β-Ni(OH) 2 . The composites had a good electron transferring and biocompatibility. The l -histidine biosensor was fabricated by drop casting the Ni(OH) 2 /ethanol solution (2.5   g   L −1 ) on the surface of the glassy carbon electrode (GCE). The prepared biosensor shows better catalytic performance compared with bulk material or other similar materials, with the detection limit of 80   nM and the linear range from 0.1   μM to 0.5   mM ( R 2   =   0.993) in a 0.1   M NaOH solution. The effects of electroactive interferents at the test conditions can be negligible which showed an excellent selectivity of the biosensor. The proposed method was also successfully applied for the determination of l -histidine in human blood serum sample. High sensitivity, excellent selectivity and ease of preparation make this sensor promising for the applications in the development of detecting some other amino acids and proteins.