Determination of tiopronin based on the enhancement of Ru(bpy)3 2+ co-reactant electrochemiluminescence

• Tiopronin was employed as a new co-reactant for Ru(bpy)32+ ECL system.
• A sensitive ECL method was established for the direct detection of tiopronin.
• This method has advantages of both high sensitivity and simple procedure.
• A possible mechanism was proposed for Ru(bpy)32+ /tiopronin system.

It was found that tiopronin could strongly enhance the electrochemiluminescence of tris(2,2’-bipyridine) ruthenium(II) (Ru(bpy)32+) in alkaline solution on a bare Pt electrode, based on which a sensitive, simple and rapid method for the determination of tiopronin was established. Under the optimal conditions, the logarithm of ECL enhancement has a linear relationship with the logarithm of tiopronin concentration in the range from 2.0×10−7 to 2.0×10−4 mol L−1 with a detection limit of 1.0×10−8 mol L−1 (S/N= 3), and the relative standard deviation of 1.6% (n=7, c=5.0×10−6 mol L−1). The proposed method has been applied to the determination of tiopronin in pharmaceutical preparations and the results were satisfactory with recoveries of 91.7±1.7%, 98.3±1.0% and 100.8±0.5%, respectively, for three different concentration levels (0.61 μmol L−1, 6.1 μmol L−1 and 12.2 μmol L−1). According to the study of electrochemical behavior, ECL behavior and ECL emission spectrum of Ru(bpy)32+/tiopronin system, a possible ECL mechanism was proposed.

Figure optionsDownload as PowerPoint slide