Table 1. Randles Circuit Parameters Calculated for Bare and Amino Acid-Modified GCEs from Electrochemical Impedance Spectroscopy (EIS).

electrodes	Rct (kΩ)	Re (Ω)	CPE (μF)	Jo (μA/cm2)	n
bare GCE	6.41 ± 0.057	201.7 ± 1.74	5.52 ± 0.54	4.01	0.79
Lys/GCE	3.34 ± 0.026	199.5 ± 1.68	2.57 ± 0.12	7.69	0.81
Glu/GCE	2.62 ± 0.025	198.2 ± 1.58	2.53 ± 0.10	9.80	0.83
Thr/GCE	1.77 ± 0.017	186 ± 1.41	2.51 ± 0.14	14.50	0.86
Ala/GCE	0.50 ± 0.007	179.8 ± 1.63	1.43 ± 0.04	51.40	0.90