Fluorescent film sensor for nitroaromatics via monolayer assembly of arylethenyl-branched s-triazine on glass slide surfaces

•Sensing molecules are grafted onto the glass surface by three anchoring groups.•The flat molecules on the glass act as spacers to minimize intermolecular action.•This monolayer sensor shows sensitive response to DNT in dilute solution.•This sensor exhibits good reversibility of sensing process.•This sensor shows no time delay to get to the quenching equilibrium.

A fluorescent compound, arylethenyl-branched s-triazine (II), is synthesized. It can be immobilized onto the glass surface with the molecule plane parallel to the surface, decreasing the π–π stacking between molecules on glass surface. Measurements of contact angle to water, XPS spectra and light absorbance of the functionalized glass confirm the success of grafting II onto the surface of the glass. The quenching efficiency of this sensor reaches 68.7% and 89.3% when CDNT in THF is 2 × 10−5 and 2 × 10−3 mol/L, respectively. From recycle 2–10, the recovered fluorescence intensity of the glass sensor remains between 72.4% and 58.0% of the original emission intensity, which implies good reversibility of the quenching process. The quenching efficiency of the glass sensor reaches 95% immediately once upon it is exposed to saturated DNT vapor, showing no time delay to get to the quenching equilibrium.

Graphical abstractAn arylethenyl-branched s-triazine has been synthesized and immobilized onto the glass surface, forming a monolayer sensor for DNT detection with speedy response and good reversibility of sensing process.Figure optionsDownload full-size imageDownload high-quality image (85 K)Download as PowerPoint slide