Dual-optical response probe to HSO3- and HClO via ICT and solvatochromic effects for food and cellular applications.

Sulfite (HSO3-) and hypochlorous acid (HClO) serve as essential food additives and key raw materials in bleaching agents. However, excessive consumption of these compounds may disrupt cellular redox homeostasis, leading to a series of adverse physical effects. Therefore, the development of reliable analytical methods to detect HSO3- and HClO levels in food products is of significant importance. In this study, we developed a hemicyanine dye-based fluorescent probe (TBA) for the sensitive and selective detection of HSO3- and HClO. The probe incorporates distinct recognition sites (a CC bond for HSO3- and an -NH2 group for HClO) operating in different solvent systems to enable dual-analyte discrimination. TBA exhibited excellent sensitivity, with detection limits (LOD) of 1.1 μM for HSO3- (60 min response) in water and 10.7 μM for HClO (40 s response) in ethanol. Furthermore, the probe was successfully adapted into a portable test strip format, demonstrating reliable quantification in real samples (recovery: 88.97-104.88 %). In addition, TBA displayed mitochondria-targeted capability, allowing its application in live cells HSO3- imaging.