Novel Rhodamine B and 2H‐benzo[b][1,4]oxazin‐3(4H)‐one‐derived Fluorescent Sensor for Low pH Value Detection

摘要

A new fluorescent probe L fusing the rhodamine B scaffold with 2H‐benzo[b][1,4]oxazin‐3(4H)‐one moiety has been developed and applied as an acidic pH sensor. The ultraviolet (UV) and fluorescence spectra of the probe at different pH values were investigated in B–R buffer/MeOH (v: v = 3: 7). This probe showed increase of both the UV–Vis absorption and fluorescence emission from alkaline/neutral to acidic condition, reaching a strongest intensity at pH 2.13, but the intensities decreased when the pH decreased to 1.83. The color variation along the pH changes proved that the probe L can be used as a low‐cost optical sensor for the naked eye detection of proton in the present buffer.