Carbon nanosphere templated Co-Gd mixed metal oxides on amine functionalized La-MOF for high performance electrochemical L-tryptophan sensing.

An exceptional electrochemical sensing platform was engineered by integration of cobalt-gadolinium mixed metal oxides (CGOs) with an amine functionalized lanthanum metal organic framework (NLF) to yield a hierarchically porous NLF@CGO hybrid. The carbon nanosphere (CNS) template provides the CGO nanoparticles with abundant active sites, while the amine functionalization in the NLF matrix provides robust anchoring with CGO to accelerate the charge transfer kinetics. The NLF@CGO hybrid modified glassy carbon electrode (NLF@CGO/GCE) exhibits outstanding sensitivity and selectivity towards L-tryptophan (L-TRP), achieving a low limit of detection (LOD) of 0.3 nM and limit of quantification (LOQ) of 1.007 nM, within the linear range of 1.7-25.5 nM. The sensor further exhibits excellent repeatability and reproducibility. Practical applicability was evaluated by real-time detection of L-TRP in synthetic urine and pharmaceutical samples, yielding favourable recovery rates of around 99%. These findings highlight the NLF@CGO hybrid as a robust and versatile architecture, offering significant promise for advanced electrochemical sensing and real-world analytical applications.