Fig. 4.

Amperometric responses of different electrodes to PNP (0.6 mmol/L) in Tris buffer solution (0.5 mol/L, pH 8.5)

(a) 1.01 V for SPE; (b) 0.99 V for GCE; (c) 0.90 V for rGO/Chi-modified SPE; (d) 0.84 V for rGO/IL/Chi electrode