Preparation of chitosan based fluorescent probe for selective recognition of formaldehyde and acetaldehyde.

Formaldehyde and acetaldehyde, as volatile organic pollutants, can seriously harm human health if exposed for a long time. Developing efficient and favorable selective detection methods is of great practical significance. This paper presents a biomass probe, AN, which uses aminated chitosan as the carrier, 4-bromo-1,8-naphthalic anhydride as the fluorophore, and hydrazine groups as the reactive sites. This probe can selectively detect formaldehyde (FA) and acetaldehyde (AA) in pure aqueous solution. AN is a turn-on probe for formaldehyde and acetaldehyde. The reaction products of AN with formaldehyde and acetaldehyde, namely AN-FA and AN-AA, respectively, exhibit distinct fluorescent signals, thereby achieving good sensitivity and favorable selectivity for detection. The detection limits of AN for formaldehyde and acetaldehyde are 3.7535 μM and 0.0622 mM, respectively. By integrating the fluorescent probe with a smartphone, rapid and visual detection is achieved, greatly enhancing the convenience and universality of the testing.