Determination of Colchicine by Amperometric Tyrosinase Immunosensors Modified with Structured Nanomaterials

Amperometric immunosensors for colchicine detection are developed using tyrosinase as a label on screen-printed graphite electrodes modified with multiwalled carbon nanotubes (MWCNTs), reduced graphene oxide (rGO), and a nanocomposite based on rGO and nickel nanoparticles (rGO/NiNP). Studies demonstrated that colchicine acts as an activator of tyrosinase over the concentration range from 100 pM to 1 μM, with a lower limit of detection of 50 pM and R2 = 0.9647. The modification of the electrode surface with carbon nanomaterials and the nanocomposite improved the analytical performance of the immunosensors: the working concentration range extended to 50 pM–1 μM for both MWCNT and rGO modifications, with lower limits of detection of 10 pM in each case, and R2 values of 0.9701 and 0.9977 for MWCNTs and rGO, respectively. For the immunosensor modified with the rGO/NiNP nanocomposite, the working concentration range was 10 pM–1 μM, with a lower limit of detection of 3 pM and R2 = 0.9995. The rGO/NiNP-modified immunosensor was successfully used to determine colchicine in model and pediatric urine samples.