Quenching of the electrochemiluminescence of Ru(bpy)32+/TPA by malachite green and crystal violet

Efficient and stable quenching of electrochemiluminescence of Ru(bpy) 3 2+ /TPA by malachite green(MG) and crystal violet(CV) at the glass carbon (GC) electrode is reported. A novel quenching mechanism has been proposed. Resonance energy transfer from the excited-state luminophore Ru(bpy) 3 2+⁎ to MG/CV and dynamic quenching are suggested as the mechanism for quenching ECL. The quenching mechanism is discussed in detail based on UV–visible absorption spectra, cyclic voltammograms, ECL curves and fluorescence methods . MG shows more efficient quenching than CV. Moreover, the quenched ECL intensity versus the concentration of MG and CV are linear over the concentration ranges of 8×10 −10 –8×10 −7   M and 3.46×10 −9 –5.5×10 −7   M, respectively. The corresponding limit of detection (LOD) was 1.0×10 −10   M for MG and 1.1×10 −10   M for CV ( S / N =3).