A dual-function fluorescent probe for the detection of pH values and formaldehyde.

A dual-function fluorescent probe (probe 1) was developed in this work for the separate detection of the pH value and formaldehyde (HCHO). Probe 1 could recognize HCHO and the pH value by amino group. The color of the probe solution was changed from gray-blue to light blue with the increase in the pH value, and the luminous intensity became bigger with the increase in the formaldehyde concentration. A curve function relationship between the fluorescence intensity and the pH value was also extracted. A smartphone containing color detector of image was used to record the value of three primary colors (R value, G value, and B value) of the probe solution in formaldehyde. Importantly, there was a linear functional relationship between the B*R/G value with HCHO concentration. Therefore, the probe can be used as a rapid tool for the detection of formaldehyde. More importantly, probe 1 was successfully used to detect formaldehyde in an actual distilled liquor sample.