Sensitively liquid and gaseous detection of formaldehyde based on a supramolecular organic framework

Because of the serious threat to human health, the development of fluorescent sensor for detection of formaldehyde (FA) has attracted great concern. Herein, a 4,4 '-(1,2-diphenylethene-1,2-diyl)dibenzoic acid-based SOF (HNU-44), has been assembled, which can be used to detect FA by quite different fluorescent response in liquid and gas. In liquid phase, HNU-44 exhibits fluorescence enhancement with the limit of detection (LOD) 27.41 ppb. On the contrary, fluorescence quenching happens when HNU-44 is exposed in the FA atmosphere with the LOD of 2.61 ppb. The LOD in gas is even lower than the air quality criterion of gaseous FA (80 ppb) recommended by World Health Organization (WHO). Furthermore, sensing tests were performed on fish samples, which means that HNU-44 can be used in actual sample. This work expands promising approach for effective FA detection both in the experiment test and actual application.