Fig. 6

Evaluation of analytical performance of the ECL immunosensor. A ECL intensity of the proposed immunosensor with 0.02, 0.1, 1.0, 10, 50, 100, 500 and 1000 pg mL^− 1 of anti-MPO. B Calibration plot of the ECL intensities vs. the log C_anti−MPO. C The cross-reactivity of the immunosensor against different interfering proteins (50 pg mL^− 1 CEA, 50 pg mL^− 1 PSA, 50 pg mL^− 1 BSA, 50 pg mL^− 1 AFP and 50 pg mL^− 1 INS) and their mixtures (50 pg mL^− 1 CEA, 50 pg mL^− 1 PSA, 50 pg mL^− 1 BSA, 50 pg mL^− 1 AFP, 50 pg mL^− 1 INS and 50 pg mL^− 1 anti-MPO). D Investigation of the stability of the immunosensor by detecting 50 pg mL^− 1 anti-MPO with 20 consecutive cycles. Data were expressed as mean ± standard deviations, sample replicates n = 3. E Long-term stability of the ECL immunosensor for anti-MPO detection in 4 mL 0.01 M PBS (pH 7.4) containing 3 mM H₂O₂ and 0.1 M K₂S₂O₈ with a potential from − 1.6 V to -0.6 V at a scan rate of 0.1 V s^− 1