Quinoline-based hydrazone derivative as a biocide chemosensor: synthesis and sensing studies

Tributyltin (TBT) is an organic biocide used on antifouling paints to avoid biofouling on boats and submersed structures. It was found that TBT was toxic to a variety of aquatic organisms, and it was banned by the Rotterdam Convention, in 1998. TBT sensing is still an important issue since it is still affecting aquatic environments, besides the fact that some countries did not sign the convention and are still using it. Current TBT monitoring methods are based on sampling and laboratory analysis, which is expensive, time-consuming, and require expert users. Therefore, a new simple and fast TBT sensing method would be of great interest.

In this work, a new quinoline-based hydrazone derivative was synthesized by a condensation reaction in 67 % yield. The new compound was characterized by the usual spectroscopic and spectrometric techniques. The preliminary chemosensory study of the hydrazone derivative in the presence of TBT in acetonitrile solution, resulted in a color change from colorless to red and the appearance of fluorescence. This interaction was confirmed by spectrophotometric and spectrofluorimetric titrations which revealed that 17 equiv. of TBT led to a maximum optical signal in terms of fluorescence intensity and absorbance.