Colorimetric Detection of Hydrogen Peroxide and Dopamine using thePeroxidase-like Activity of MOF-2

Introduction:: Dopamine (DA) is a crucial neurotransmitter in neurological and cardiovascular functions. Accurate measurement of DA in bodily fluids is essential for diagnosing conditions such as Parkinson's disease, schizophrenia, Alzheimer's disease, and heart failure. Traditional colourimetric methods that utilise horseradish peroxidase (HRP) to oxidise 3, 3’, 5, 5’-tetramethylbenzidine (TMB) face limitations, including instability and purification challenges. Recently, MOFs have emerged as promising alternatives due to their stable structures and ease of storage. This study aims to develop a stable colorimetric method for detecting dopamine (DA) and hydrogen peroxide (H2O2) in human serum using MOF-2 for the first time. method: This study, MOF-2, was synthesised via a solvothermal method, followed by characterisation using FT-IR, SEM, and XRD techniques. The peroxidase-like activity of MOF-2 was assessed in a TMB and H2O2 system within an acetate buffer. Factors influencing this activity, including reaction time, pH, TMB concentration, and MOF-2 quantity, were systematically optimised. A calibration curve was established to measure H2O2 and DA in human serum samples, and the linear range, limit of detection (LOD), and limit of quantification (LOQ) were calculated. result: The optimised method for H2O2 detection exhibited a linear range of 0.76 to 1200 μM, with a detection limit of 0.25 μM and recovery rates between 92.71% and 116.85%. For DA detection, the method showed a linear range of 16.15 to 108.29 μM, a LOD of 0.09 μM, and recoveries ranging from 95.74% to 115.78% in human serum samples. Discussion:: MOF-2 possesses significant peroxidase-mimicking activity, enabling robust and sensitive detection of H₂O₂ and DA. This method offers advantages over traditional HRP-based approaches in terms of stability, cost-effectiveness, and ease of preparation. Limitations include the need for further validation in clinical settings and comparison with standard diagnostic tools. Conclusion:: MOF-2 demonstrated significant peroxidase-like activity, successfully developing a reliable colorimetric method for determining H2O2 and DA in biological samples.