Aminoalkanethiol surface modifiers were investigated on gold electrodes. It was established, that quinone molecules could be attached to these surface layers in three different forms with well-distinguished redox potentials. Chemical reaction with the amino groups of the modifiers could produce monosubstituted and disubstituted quinones attached covalently to the layers. However, a third form could be detected, as well that seems to be quinone attached non-covalently to the monosubstituted quinone molecules.