Fig. 3.

The two-step CL production by TCBQ/H₂O₂ was well-correlated to and directly dependent on its two-step hydroxyl radical production. (A and B) The ESR and fluorescent kinetic study on ^•OH production by TCBQ/H₂O₂. TCBQ, 0.1 mM; TrCBQ–OH, 0.1 mM; H₂O₂, 1 mM; DMPO, 100 mM; 3-CCA, 4 mM. (C) ESR detection of ^•OH production by TCBQ/H₂O₂ and TrCBQ–OH/H₂O₂. TCBQ, 0.5 mM; TrCBQ–OH, 0.5 mM; H₂O₂, 5 mM; DMPO, 100 mM. (D) The pH-dependent ^•OH production by TCBQ/H₂O₂ by fluorescent method. TCBQ, 0.1 mM; H₂O₂, 1 mM; 3-CCA, 1 mM. (E) The CL production by TCBQ/H₂O₂ was quenched by the classic ^•OH scavengers. TCBQ, 0.1 mM; H₂O₂, 100 mM. (F) CL production by TCBQ/H₂O₂ was further enhanced by addition of Fe(II)–EDTA. TCBQ, 0.1 mM; H₂O₂, 100 mM. All reactions were carried out in Chelex-pretreated phosphate buffer (0.1 M, pH 7.4).