Responsive Ruthenium Complex Probe for Phosphorescence and Time-Gated Luminescence Detection of Bisulfite
Sensitive and selective quantification of a specific analyte is of great significance in analytical and environmental sciences, as well as in food industries. Herein we report the design, synthesis, characterization, and application of a responsive ruthenium(II) complex probe, Ru-azo, for phosphorescence and time-gated luminescence (TGL) detection of bisulfite, an important additive in food industries. After the specific nucleophilic addition reaction between bisulfite and azo group of Ru-azo, a new ruthenium(II) complex Ru-SO3 was afforded, which resulted in the remarkable increase in phosphorescence intensity, allowing the bisulfite detection to be achieved. In addition, long-lived emissions of Ru-azo ( = 258 ns) and Ru-SO3 ( = 261 ns) also enabled the TGL detection of bisulfite in autofluorescence-rich food samples. Through theoretic computations, photoinduced electron transfer (PET) process within the ruthenium(II) complex was validated, which unveiled the rationality of luminescence “off-on” response of Ru-azo to bisulfite. The probe showed advantages of good water solubility, and high sensitivity, selectivity and accuracy for responding to bisulfite, facilitated its application in phosphorescence and TGL detection of bisulfite in aqueous and food samples.