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 (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 mu M to 8.5 mM) with a limit of detection of 2.74 mu M. 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.

Automated summary

In this work, a composite probe (CDs@ZIF-90) based on carbon dots (CDs) and zeolitic imidazolate framework-90 (ZIF-90) is constructed to ratiometrically detect bisulfite (HSO3-) and sulfite (SO32-). The proposed strategy shows a broad linear range (10 μM to 8.5 mM) and a low limit of detection (2.74 μM) for HSO3-/SO32- determination. The strategy is successfully applied for evaluating HSO3-/SO32- in sugar with satisfactory recoveries.