Fluorescence Turns on-off-on Sensing of Ferric Ion and L-Ascorbic Acid by Carbon Quantum Dots

This study used a hydrothermal approach to create sensitive and focused nanoprobe. Using an “on-off-on” sensing mechanism, the nanoprobe was employed detect quantify ferric ions L-ascorbic acid. Synthesis of carbon quantum dots achieved with single step at 180°C for 24 hours using hot pepper as starting material. The prepared CQDs showed high fluorescence yield 30% when excited 350 nm, exhibiting excitation-dependent fluorescence. emission can be quenched by adding ions, which attributed complex formation leading nonradiative photoinduced electron transfer (PET). Adding acid, convert into ferrous break complex, restore CQD. linear range LOD were (10–90) ?M 1 respectively, acid’s (5–100) while 0.1 quantification both substances accomplished. In addition, orange fruit actual sample source ascorbic acid analysis, yielding up 99% recovery.