Figure 5 Thin-layer cyclic voltammograms of approximately 0.5 µm Mb-DLPC film on PG electrode at 2Vs and 25°C in buffers of different

Mb gave direct, reversible heme FeIII/FeII electron transfer in all films of double-chain (e.g., DDAB, DMPC and DHP) [11, 18-20, 26] or triple-chain surfactants [27] on PG, Au, ITO, or Pt surfaces. These electrodes do not give significant voltammetric peaks in a nominally pure Mb solution. However, quasireversible peaks developed after several hours of storage and repetitive scanning of PG electrodes in Mb solutions [28]. Also, quasireversible voltammetry of Mb can be obtained with freshly purified solutions on specially cleaned “hydrophilic” ITO electrodes [29] and on PG electrodes [19]. Without ultrahigh Mb purity, considerably slower electron transfer was found on ordinary ITO [30].