A wide-range ratiometric sensor mediating fluorescence and scattering based on carbon dots/metal–organic framework composites for the detection of bisulfite/sulfite in sugar

Bisulfite (HSO 3 − ) and sulfite (SO 3 2− ) are commonly employed in food preservatives and are also significant environmental pollutants. Thus, developing an effective method for detecting HSO 3 − /SO 3 2− is crucial for food safety and environment monitoring. In this work, based on carbon dots (CDs) and zeolitic imidazolate framework‐90 (ZIF‐90), a composite probe (named CDs@ZIF-90) is constructed. The fluorescence signal and the second-order scattering signal of CDs@ZIF-90 are employed to ratiometricly detect HSO 3 − /SO 3 2− . This proposed strategy exhibits a broad linear range for HSO 3 − /SO 3 2− determination (10 µM to 8.5 mM) with a limit of detection of 2.74 μM. This strategy is successfully applied for evaluating HSO 3 − /SO 3 2− in sugar with satisfactory recoveries. Therefore, this work has uniquely combined the fluorescence and second-order scattering signals to establish a novel sensing system with a wide linear range, which is applicable for ratiometric sensing of HSO 3 − /SO 3 2− in actual samples. Graphical Abstract