A Coumarin-based Ratiometric Fluorescent Probe for Differentiating Sulfites and Hydrogen Sulfide

KeyWord:fluorescent probe  sulfite  hydrogen sulfide  differentiation

Abstract:

      A ratiometric fluorescent probe MSP,based on Michael addition reaction and intramolecular charge transfer mechanism,was fabricated for the differentiated determination on sulfite and hydrogen sulfide.A strong electron with draw group malononitrile was conjugated to coumarin fluorophore,which activated the electrophilic activity of the C¡¬C double bond,and strengthened the electron push-pull effect of the probe.As a result,obvious red-shifts in absorption and emission maxima,and great acceleration of the reaction rate between sulfite and the probe could be expected,which enabled MSP to detect sulfite rapidly.As prolonging the assay time to 3 h,the presence of hydrogen sulfide led to obvious blue-shifts in absorption and emission maxima along with significant fluorescence enhancement,and about 260-fold enhancement of the ratio of fluorescence intensities at 510 nm and 690 nm was observed.It is possible to make distinguishment between sulfite and hydrogen sulfide at different response time and different spectral channels.The probe exhibited excellent selectivity and competition toward sulfite and hydrogen sulfide.Good linear relationships between A464/A572 and sulfite,and I510/I690 and hydrogen sulfide over the concentration ranges of 0-200 ¦Ìmol/L and 0-500 ¦Ìmol/L were obtained,respectively.The detection limits for sulfite and sulfide were estimated to be 0.95 ¦Ìmol/L and 0.6 ¦Ìmol/L,respectively.In addition,the probe could be used for bioimaging sulfite and hydrogen sulfide in living cells.