Recent development of hydrogen sulphate (hso4-) targeting fluorescent chemosensor using different approaches

Chemical sensors typically depend on fluorescent dyes, chromogenic compounds and metal complexes for analyte (HSO4-) induced signaling systems. These sensors involve binding or recognition event into a spectroscopic signals upon the introduction of hydrogen sulphate. There are some conventional methods for the detection of hydrogen sulphate but among these conventional methods, fluorescent chemosensors have become powerful tools for sensing of small samples due to their simplicity, sensitivity, low-toxicity, easiness of operation and working in pure aqueous media and which are applicable in both in vitro and in vivo use in recent years. Here we have tried to recapitulate the use of several organic molecules in the field of colorimetric and fluorescent HSO4- anion sensing that continues to be an important goal and is being pursued by a number of research groups worldwide. The present highlight provides an overview of different photophysical properties involved in the sensing of HSO4- ions leading to easy to observe naked eye colorimetric as well as fluorescence change. In addition to organic synthesized molecules, we have also shown here some metal complexes that are able to act as a superior HSO4- ions sensor. Some of the chemosensors are significantly capable to detect the distribution of hydrogen sulphate ions in vitro in living cells in aqueous medium at biological pH by fluorescence imaging studies.