Background and Objective: Melamine is a chemical compound commonly used as an adulterant in food products. In this study, a fluorescence-based sensor utilizing an aluminum metal-organic framework (Al−MOF) was developed for the detection of melamine in milk powder.
Materials and Methods: In this study, Al-MOF was employed as a sensing material due to its high fluorescence properties and strong ability to adsorb melamine. Using fluorescence techniques, the sensitivity and selectivity of the sensor towards melamine were evaluated over a concentration range of 0 to 400 nanomolar (nM).
Results: The melamine concentration was determined based on the reduction in the fluorescence intensity of the Al-MOF. The effects of different parameters such as pH, reaction time, and concentration, on the performance of the designed sensor were evaluated. Under optimized conditions (pH = 9, reaction time < 1 min, and Al–MOF concentration of 30 mg/L), a good linear relationship (R2 = 0.99) was observed between fluorescence intensity and melamine concentration in the range of 0–400 nM, with a detection limit of 38.5 ppb. However, the limit of detection (LOD) for HPLC method was approximately 90 ppb, indicating that the designed sensor has higher sensitivity (about 2.3 times). The sensor also exhibited good selectivity for melamine. The recovery percentage and relative standard deviation (RSD) were found to be 97-103% and 1.2-2.8%, respectively.
Conclusion: This sensor can serve as an effective tool for quality control in dairy products due to its simplicity and rapid detection capabilities.
