Fluorescent Sensing for the Detection and Quantification of Sulfur-Containing Gases

Sulfur-containing gases, such as H₂S and SO₂, play significant roles in a multitude of biological processes affecting human life and health. Precise and efficient detection of these gases is therefore crucial for advancing one's understanding of their biological roles and developing effective diagnostic strategies. Fluorescent sensing offers a highly sensitive and versatile approach for detecting these gases. This Review examines the recent advances in the fluorescent detection of H₂S and SO₂, highlighting the key mechanisms involved in fluorescence signal transduction, including changes in intensity and wavelength shifts. The diverse array of probe molecules employed for this purpose, including those utilizing mechanisms such as nucleophilic reactions, Förster resonance energy transfer (FRET), and sulfur affinity interactions are explored. In additional to organic sensors, the focus of the Review is particularly directed toward quantum dot (QD) systems, emphasizing their tunable optical properties that hold immense potential for fluorescence sensing. Beyond the traditional III-V QDs, we delve into the emerging fluorescence sensors based on halide perovskite QDs, upconversion nanocrystals, and other novel materials. These advanced QD systems hold promise for the development of highly sensitive and cost-effective gas detectors, paving the way for significant advances in biomedical and environmental monitoring. This Review provides a comprehensive overview of the current state-of-the-art in QD-based fluorescence sensing of sulfur-containing gases and provides a multifaceted discussion comparing organic fluorescent sensors with QD sensors, highlighting the key challenges and opportunities for the integration of fluorescence sensing as it evolves. The Review aims to facilitate further research and development of innovative sensing platforms to enable more accurate and sensitive detection of these important gases.