Coumarin hemicyanine-based colorimetric, smartphone color ratio, and intramolecular charge transfer fluorescent receptor for highly specific sensing of hydrazine in environmental water samples

In this report, we focused on developing a fluorescent probe based on coumarin hemicyanine (CPR) and a smartphone-based colorimetric sensing system for detecting hydrazine in actual water sample analysis. The receptor CPR was successfully synthesized, characterized by various spectroscopic analyses, and also applied for selective, sensitive, quantitative, colorimetric, and fluorometric sensing of hydrazine in DMF/water, 4:3 (v:v) ratio. The basic nature of hydrazine is an idyllic analyte and can be predicted to bind with the receptor CPR. Remarkably, as synthesized compound, CPR displays excellent structures of bluish-green emission, large Stokes shift, rapid emissive response to hydrazine (120 s), and good photophysical nature. Additionally, the addition of hydrazine in incremental quantities to CPR results in considerable emission quenching of about 92.3%, which modifies the colorimetric features of CPR. The smartphone-assisted red, green, and blue (RGB) values-based colorimetric sensing techniques were made to follow the colorimetric changing behavior of CPR with hydrazine. Most crucially, this technique was also used to keep track of real water samples containing hydrazine, such as tap water and drinking water samples.