The thin-layer flow cell consisted of three electrodes: a BDD working electrode, a Ag/AgCl reference electrode (Bioanalytical System Inc., USA) and a stainless steel tube counter electrode. The geometric area of the BDD electrode in the flow cell was estimated
to be 0.37cm2 using a 1-mm thick silicon rubber gasket as a spacer.The measurement step was performed in a copper Faradaic cageto reduce the electronic noise. An Autolab Potentiostat 30 (Ecochemie Netherland) was used for amperometric control and signal
processing.