First Report for Levodopa Electrocatalytic Oxidation Based on Copper Metal‐Organic Framework (MOF): Application in a Voltammetric Sensor Development for Levodopa in Real Samples

Levodopa (LD) determination was achieved for the first time by a cooper metal‐organic framework (MOF) based nanocomposite modified electrode. This research describes a simple, sensitive and cost‐effective electrochemical method for the detection of LD in real samples and the laboratory samples. This method is based on LD oxidation on glassy carbon electrode (GCE) surface modified with multi‐walled carbon nanotubes and copper terephthalic acid MOF (MWCNTs/Cu (TPA) MOF) nanocomposite. MOF was synthesized by the hydrothermal method. The synthesized MOF was characterized by Fourier‐transform infrared spectrophotometry (FT‐IR), energy‐dispersive X‐ray spectroscopy (EDX), field emission scanning electron microscopy (FESEM) and X‐ray diffraction (XRD). Electrochemical studies were accomplished by square wave voltammetry (SWV) and cyclic voltammetry (CV). The applied MOF, as a Cu‐containing synthetic peroxidase enzyme, can electrocatalyze oxidation of LD on the electrode surface and in incorporation with MWCNTs illustrated satisfactory synergic electrocatalytical properties which leads to sensitive detection of LD in the human serum sample. Limit of detection (LOD), sensitivity and linear range were 2 nmol L–1, 2.26 μA/μmol L–1 and 0.9‐35 μmol L–1 respectively, which in compared to other enzymatic or non‐enzymatic sensors were completely satisfying. Ultimately, stability, repeatability and reproducibility of as‐prepared sensor were investigated and the results were acceptable. This research reports first Cu MOF based voltammetry sensor for Levodopa determination in laboratory and real samples. Copper terephthalic acid MOF (Cu (TPA) MOF was hydrothermally synthesized and instrumentally characterized then the sensor fabricated by a glassy carbon electrode modification with MWCNTs and MOF nano composite. Linear range, detection limit, stability and applicability of developed sensor were completely satisfying.