Electrocatalytic studies of covalently immobilized metal tetra-amino phthalocyanines onto derivatized screen-printed gold electrodes

Metal tetra-amino phthalocyanine complexes (MTAPc; where M is Co or Mn) were immobilized on screen-printed gold electrodes pre-modified with mono-layers of benzylamino groups. The functionalized electrodes were then activated using benzene-1,4-dicarbaldehyde as a linker before MTAPc complexes were immobilized. The surface coverages for the modified electrodes confirmed the perpendicular orientation of the MTAPcs. The apparent electron transfer constant (k(app)) for the electrodes is 2.2x10(-5) cm.s(-1) for both CoTAPc and MnTAPc modified electrodes as calculated with data from impedance measurements. The kapp values for the bare and benzylamino modified electrodes were found to be 1.2x10(-4) cm.s(-1) and 4.9x10(-6) cm.s(-1), respectively. The electrocatalysis of the modified electrodes towards detection of H2O2 gave significant peak current densities and electrocatalytic potentials at -0.28 V and -0.31 V for the MnTAPc and CoTAPc modified electrodes, respectively.