Zr-NDI MOF Based Optical and Electrochemical Dual Sensor for Selective Detection of Dopamine

Abnormal dopamine levels severely affect the functioning of the central nervous system, and it is imperative to design a suitable sensor to diagnose the disease at the earliest. Metal–organic frameworks (MOFs) with high surface area and pore tunability have attracted wide attention in sensing applications. In this work, a Zr-NDI-based MOF and its composite Zr-NDI/MWCNT have been studied for the dual sensing of dopamine using fluorescence and electrochemical techniques in an aqueous phosphate buffer solution. The limit of detection (LOD) of 2 μM and 0.6 μM was achieved using MOF and Zr-NDI/MWCNT with fluorescence microscopy and differential pulse voltammetry (DPV) methods, respectively. The sensor shows excellent selectivity and sensitivity in the presence of the most common interfering analytes, such as uric acid and ascorbic acid. Notably, the sensor also displayed remarkable stability with almost 95% retention in the recyclability tests and a good recovery rate (99–105%) in the presence of a real urine sample.