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.

ABSTRACT

Bisulfite (HSO3-) and sulfite (SO32-) are commonly employed in food preservatives and are also significant environmental pollutants. Thus, developing an effective method for detecting HSO3-/SO32- 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 HSO3-/SO32-. This proposed strategy exhibits a broad linear range for HSO3-/SO32- determination (10 µM to 8.5 mM) with a limit of detection of 2.74 µM. This strategy is successfully applied for evaluating HSO3-/SO32- 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 HSO3-/SO32- in actual samples.