Ratiometric pyrene-based fluorescent sensor for on-site monitoring of formaldehyde in foods and living cells

Abstract

A ratiometric pyrene-based fluorescence sensor PN was developed for visual detection of formaldehyde (FA) by featuring homoallylamino group as specific recognition site. Sensor PN undergo a unique FA-triggered 2-aza-Cope rearrangement, which resulted in monomer-excimer conversion in a ratiometric manner accomplished with distinguishable fluorescent color change from blue to violet. Due to the advantage of high selectivity, fast response (< 100 s), low detection limit (18 μM), wide quantitative detection range (0.018–4 mM) and large ratio enhancement (up to 10-fold), PN has been successfully applied for detecting FA in diverse food samples. Notably, novel portable devices based on paper chip and alginate gel were constructed and realized visual quantitative detection of liquid and gaseous FA, as well as nondestructive monitoring volatile FA variation of real food samples during their shelf life, which were verified with the aid of chemometrics. Most importantly, sensor PN has been proven to be capable of fluorescence imaging of FA in living cells. Therefore, the impressive sensor PN is expected to provide advice and insights in the field of food safety and biological systems analysis.