(A) Cyclic voltamperograms of 5 mM ascorbic acid in 0.1 M KCl in water with (a, black) regular flat ITO and nanofibers electrospun at 10 kV for (b, red) 5 and (c, blue) 20 min. (B) Cyclic voltamperograms of ascorbic acid in rising concentrations: (black) 0 mM, (red) 0.05 mM, (blue) 0.3 mM, (pink) 0.5 mM, (green) 1 mM and (dark blue) 3 mM in 0.1 M KCl in water on a nanofiber layer electrospun for 20 minutes at 10 kV and thermally treated at 1000 °C under nitrogen. Inset: corresponding calibration curve. The scan rate was 50 mV s−1 for all measurements. Electrode area was equal to 12.6 mm2. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)