Determination of bergenin based on the electrochemiluminescence quenching of tris(2,2′‐bipyridine)‐ruthenium(II)

Quenching effects of bergenin, based on the electrochemiluminescence (ECL) of the tris(2,2′‐bipyridyl)‐ruthenium(II) (Ru(bpy) 3 2+ )/tri‐n‐propylamine (TPrA) system in aqueous solution, is been described. The quenching behavior can be observed with a 100‐fold excess of bergenin over Ru(bpy) 3 2+ . In the presence of 0.1 m TPrA, the Stern–Volmer constant ( K SV ) of the ECL quenching is as high as 1.16 × 10 4 M −1 for bergenin. The logarithmic plot of the inhibited ECL versus logarithmic plot of the concentration of bergenin was linear over the range 3.0 × 10 −6 –1.0 × 10 −4 mol/L. The corresponding limit of detection was 6.0 × 10 −7 mol/L for bergenin (S/N = 3). In the mechanism of quenching it is believed that the competition of the active free radicals between Ru(bpy) 3 2+ /TPrA and bergenin was the key factor for the ECL inhibition of the system. Photoluminescence, cyclic voltammetry, coupled with bulk electrolysis, supports the supposition mechanism of the Ru(bpy) 3 2+ /TPrA–bergenin system. Copyright © 2015 John Wiley & Sons, Ltd.