2-(Dibutylamino)ethyl acrylate as a highly efficient co-reactant of Ru(bpy)32+ electrochemiluminescence for selective detection of cysteine

A highly efficient co-reactant of Ru(bpy)32+ electrochemiluminescence (ECL), 2-(dibutylamino)ethyl acrylate(DBAEA), was successfully synthesized by a straightforward one-step reaction between dibutylaminoethanol and acrylyl chloride. On account of the interaction between the olefin group of DBAEA and Pt electrode, the ECL intensity utilizing DBAEA as the co-reactant was increased dramatically, nearly as 10 times and 17 times as conventional co-reactants dibutyaminoethanol and tripropylamine. Since cysteine can remove the acrylate group of DBAEA specifically through conjugated addition/cyclization reaction, the ECL intensity of Ru(bpy)32+/DBAEA was declined selectively. Therefore, cysteine was detected through this novel ECL system with high selectivity towards other amino acids. The linear range was between 10 μM and 200 μM with a limit of detection of 1.15 μM. The cysteine in Dulbecco’s Modified Eagle Medium (DMEM) was detected and satisfying recovery was obtained.