A susceptible multifunctional fluorescent probe based on levulinic acid for the practical detection of SO₂

Sulfites (HSO₃^-) are used as preservatives and additives in many foods and medicines. However, a high sulfite concentration can cause asthma attacks and even breathing difficulties. Sulfites can also accumulate from the environment into the body, so it is necessary to develop a probe capable of detecting SO₂ in the environment and in organisms. A multifunctional sensor, SO-2, based on levulinic acid was designed and synthesized. SO-2 showed an excellent response to SO₂ with a detection limit of 2.0 × 10^-8 M and a fast response equilibrium time (within 10 min), which indicated that the probe could detect SO₂ with high sensitivity. The probe also successfully traced exogenous bisulfite in cells and was applied to analyze water samples in a natural environment.