Synthesis of Reaction-Based Amine Fluorescent Probe and the Effect of Its Amino-Substitution Position on Formaldehyde Detection Performance

A novel of reaction-based amine fluorescent probe PA was prepared using 2-(phenylethynyl)pyridine as fluorophore and amino group as acceptor. The fluorescent probe achieves rapid detection of formaldehyde through a fluorescence quenching from C=N isomerization and rotation, and the different formaldehyde detection performance of 2-(pyridin-2-ylethynyl)aniline PA-1, 3-(pyridin-2-ylethynyl)aniline PA-2 and 4-(pyridin-2-ylethynyl)aniline PA-3 revealed that the position of amino recognition group on the benzene ring of 2-(phenylethynyl)pyridine has a significant impact on the detection ability of this type fluorescent probe. When the amino group is in the ortho-position of the benzene ring, PA-1 can undergo fluorescence quenching within 120 s with a limit of detection as low as 85 nM, it is a potential formaldehyde fluorescent probe; when the amino group is located in meta-position of benzene ring, the detection ability of PA-2 on formaldehyde is slightly lower than PA-1; when the amino group is at the para-position of benzene ring, PA-3 has almost no detection effect on formaldehyde. The above results provide a theoretical basis for design and synthesis of reaction-based amine fluorescent probe.