A pyrene–N-phenylparaphenylene diamine-based imine conjugate for the detection of trace amounts of water in organic solvents: real-time application in honey samples

Abstract

A one-step condensation procedure in the presence of green solvent EtOH was used to make a pyrene-based fluorescent sensor (PNPD). It could be used as a rapid, low-cost, selective, and sensitive chemodosimetric probe to detect water content. PNPD showed a cyan-blue emission in the presence of water due to cleavage of the imine bond, thus giving back the emission of pyrene carboxaldehyde. It displayed a relative error percentage of less than x ± 0.5% for the percentage detection of water content with noticeable DL and QL as compared to the reported works. A normalised approach was also developed to address the lack of knowledge in the quantitative detection of water content in an unknown sample. This approach can be used with any solvents and instruments, making it a quick, cost-effective, sensitive, and selective water sensing technique. The findings revealed that PNPD can detect water in polar, non-polar, protic, and aprotic solvents, with the detection limit and quantitation limit preferring polar aprotic solvent ACN and dioxane in both higher and lower water content. Also, we have developed a method for quantitative detection of water content in organic solvents by fluorescence studies. The real-time applicability of PNPD has been analysed by taking honey as an example, and a detection limit of 0.206 v% and quantitation limit of 0.624 v% have been found.