Carbon quantum dots applied to the chemical sensing of cobalt ions and methylcobalamin

This study demonstrates the use of Carbon Quantum Dots (CQDs) as a fluorescent sensing platform for detecting cobalt ions (Co²⁺) and methylcobalamin (MC). Synthesized via a hydrothermal method, the CQDs exhibited high dispersibility, biocompatibility, and low toxicity, with an average size of 4.3 ± 1.55 nm and a quantum yield of 8%. The detection strategy achieved limits of detection of 0.86 mmol L-1 for Co²⁺ and 1.016 μmol L-1 for MC, both below WHO limits for drinking water. The CQDs effectively identified Co²⁺ and MC in tap water samples with a recovery range of 95%-105% and a 95% confidence level, highlighting their potential for sensitive chemical sensing applications.