Two benzo-fused ring fluorescent probes for the detection of formaldehyde and its application in growing mung bean sprouts

To detect formaldehyde (FA) in food samples, two fluorescent probes with benzofused rings were created: probe 1 contains the naphthalene ring, while probe 2 has the benzimidazole ring. Probes 1 and 2 are both capable of reacting with FA to produce hydrazone molecules. The linear correlation between Probe 1 and FA (0–60 μM) was good. The fluorescence intensity at 538 nm grew as the quantity of FA increased, and the probe solution gradually turned from dark yellow to bright yellow when exposed to UV light at 365 nm. The probing solution showed a linear relationship between the luminescence intensity of the rhizomes of mung bean sprouts grown in varying concentrations of formaldehyde aqueous solution and FA. Both the luminescence intensity of the probe 2 solution under UV light and the fluorescence intensity of probe 2 and FA (0–25 μM) at 554 nm were increased. The soaked mung bean sprouts’ B value investigation showed a linear relationship with FA as well. Thus, two practical instruments for identifying FA in food samples are probes 1 and 2.