Determination of Gaseous Sulfur Dioxide and Its Derivatives via Fluorescence Enhancement Based on Cyanine Dye Functionalized Carbon Nanodots

The development of convenient methods for sulfur dioxide and its derivatives analysis is critically important because SO₂ causes worldwide serious environmental problems and human diseases. In this work, we show an unprecedented example of an energy-transfer-based fluorescence nanoprobe for selective and quantitative detection of SO₂, through molecular engineering of the fluorescent carbon nanodots by a cyanine dye which have a unique reactivity to bisulfite, achieving a detection limit of 1.8 μM with a linear relationship (<i>R</i>² = 0.9987). The specific detection was not interfered with other potential coexisted species. In addition, the probe is demonstrated for the determination of SO₂ gas in aqueous solution as well as for visually monitoring of SO₂ gas in air. This nanomaterial based probe is easily prepared, fast responding, and thus potentially attractive for extensive application for the determination of SO₂ and other similar air pollutants