Electrochemical measurements of FLBP modifications using isocyanates

The electrochemical behavior of modified FLBP was investigated using a potentiostat-galvanostat (VMP-300, Bio-Logic, France) with EC-Lab software (v11.50). Measurements were carried out in a three-electrode configuration (Pt wire as the counter electrode, Ag/AgCl wire as a pseudo-reference electrode) under an inert atmosphere. 
 A 5 mM solution of the inner-sphere redox mediator [Fe(CN)₆]³⁻/⁴⁻ in 1 M KCl was used. This solution was prepared by mixing two salts: 2.5 mM K₃[Fe(CN)₆] and 2.5 mM K₄[Fe(CN)₆].
Cyclic voltammetry (CV) tests were conducted within a potential range of -0.25 V to +0.7 V (vs Ag/AgCl in 1 M KCl) at various scan rates: 5 mV s⁻¹, 10 mV s⁻¹, 25 mV s⁻¹, 50 mV s⁻¹, 100 mV s⁻¹, 150 mV s⁻¹, 200 mV s⁻¹, and 300 mV s⁻¹.
Electrochemical impedance spectroscopy (EIS) was performed by measuring the system’s electrical response at its open-circuit potential. The measurements covered a broad frequency range from 0.01 Hz to 100 kHz, with a sinusoidal amplitude of 10 mV.