Cobalt–Neodymium Coordination Frameworks as Efficient Platforms for Sensitive Electrochemical Detection of Carmoisine

Cobalt-neodymium coordination frameworks (Co-Nd CFs) were synthesized via a solvothermal approach and employed for the sensitive electrochemical detection of carmoisine (CAR) in food samples by modifying a glassy carbon electrode (GCE). Co-Nd CFs' structural and morphological characteristics reveal an amorphous framework with a spherical-shaped mesoporous profile. The proposed detection was conducted using a B-R buffer solution pH of 7.0 in optimal conditions using a three-electrode system. Conversion of an azo-enol into a keto hydrazone, mediated by the modified Co-Nd CFs/GCE, enables a sensitive and linear response toward CAR. An acceptable detection limit (LOD) of 0.0557 μM, with a quantification limit (LOQ) of 0.1863 μM, was observed in the concentration range of 0.33 to 6.7 μM. The findings disclose high stability (RSD = 3.996%) and reproducibility (RSD = 3.95%) upon CAR detection. This is due to the Co-Nd CFs/GCE high ionic conductivity, enhanced mass transport, and large electroactive surface area and the potent synergistic interactions between Co and Nd ions. Overall, the proposed platform is suitable for real-world electrochemical analysis and offers a viable solution for detecting trace levels of synthetic food colorants.