Electrogenerated chemiluminescence for determination of indole and tryptophan

Indole and tryptophan produce electrogenerated chemiluminescence (ECL) at a Pt electrode under triangular pulse voltage when using KCl as the supporting electrolyte; the intensity was enhanced in the presence of ca. 10−2 mol 1−1 H2O2. The effects of electrochemical parameters, solution and interference conditions are investigated in detail. Under the optimum conditions, the detection limit (signal: noise = 3) for indole and tryptophan was 1 × 10−7 mol 1−1, with the linear calibration range extending up to 8 × 10−5 mol l−1.