Performance of various blocking agents (G+T=0.8% gelatin + 0.05% Tween 20; E=1 M ETA; G=0.1% gelatin and CF= a CF blocking solution) applied for 30 min on the electrode modified with covalently immobilized antibody (from 40 μL of 20 ng/mL stock solution incubated for 30 min) to resist non-specific SNA lectin interactions compared to the biosensor without any blocking agent applied (NO). In this work, SNA lectin with concentration of 0.5 mg/mL was applied for 30 min to test performance of the blocking agents. 100% was set to the response value obtained without addition of any blocking agent, i.e. labelled as NO. The EIS measurements were recorded at 50 different frequencies (from 0.1 Hz up to 100 kHz), applying a 200 mV a.c. voltage in a freshly prepared and filtered electrolyte containing 5 mM potassium hexacyanoferrate(III), 5 mM potassium hexacyanoferrate(II) and 10 mM PBS (pH 7.4). All measurements were performed at RT (~25°C) and each sample was analyzed at least in triplicate, showing results with standard deviation (SD).