Ultra-sensitive detection of Cu²⁺ in water and infant formula using a carbon dot-embedded MIL-53...

This study synthesises a novel N-CQDs@MIL-53 composite via a hydro-thermal method for fabricating an electrochemiluminescence (ECL) sensor to detect Cu²⁺ ions. The sensor delivers remarkable performance in detecting Cu²⁺ ions, achieving a broad detection range from 5 × 10^-8 to 1 × 10^-4 mol/L and a remarkable limit of detection of 1.44 × 10^-8 mol/L. This innovative approach exhibits high efficiency in analysing Cu²⁺ both in infant formula and water samples, yielding results comparable to those obtained using the standard ICP method. Notably, the N-CQDs@MIL-53 composite based ECL sensor outperforms its counterpart fabricated using standalone N-CQDs, offering enhanced sensitivity and a wider linear detection range. Moreover, the integration of N-CQDs into MIL-53 considerably enhances the composite's storage stability. This approach provides a simple, and cost-effective strategy for Cu²⁺ analysis in actual samples; in addition, it introduces a key concept of enhancing the performance of CQD-based ECL sensors by incorporating them into metal organic frameworks (MOFs).