Electrochemical sensor based on coordination compound [Co(BDC)]n allows detection of catecholamine neurotransmitter associated with neurological disorder from biological samples

Abstract

The neurotransmitter dopamine (DA) plays a crucial role as a messenger in the brain and various organs. Assessing DA levels in biological fluids is critical to identifying stress-related disorders, substance abuse, and neurochemical imbalances. Monitoring DA levels in urine and saliva samples is crucial for diagnosing neurological disorders. In this study, we successfully synthesized and confirmed a novel electrochemical sensor based on the coordination compound Cobalt-benzenedicarboxylate, [Co(BDC)], through extensive characterization via Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDS) and Thermogravimetric Analysis (TGA) analyses. Using this material, it was developed an electrochemical sensor ([Co(BDC)]/CPE) for DA detection from biological samples (urine and saliva). After optimizing the main parameters, DA was detected using an electrode modified with 25 % (m/m) [Co(BDC)] in pH 6 solution, with an applied potential increment of 5 mV, a frequency of 75 Hz and a amplitude of 100 mV. The sensor demonstrated satisfactory performance in urine samples with limit of detection (LOD) and limit of quantification (LOQ) of 1.7 μmol/L and 5.7 μmol/L, respectively. In saliva samples, the LOD and LOQ were 0.5 μmol/L and 1.7 μmol/L, respectively, with good linearity (R > 0.9922), indicating a strong linear relationship between analyte concentration and sensor response. Recovery rates between 84.9 % and 97.1 % indicate the reliable accuracy of the modified electrode in detecting DA, with relative standard deviation (RSD) < 8.0 % (n = 3) in complex samples. This method shows potential for practical applications in analyzing real samples contributing for diagnosing neurological diseases associated with this neurotransmitter.