Potentiometric responses of the silver ion-selective electrode for the (a) control (zero target), (b) 20 μg/mL myoglobin, (c) 20 μg/mL lysozyme (as a noncomplementary targets), (d) 2.5 μg/mL mouse IgG, and (e) 5 μg/mL mouse IgG (as complementary targets) after sandwich immunoassay with 5 min silver enhancement (A). Inset B: potentiometric responses of silver ion-selective electrode to (a) 20 μg/mL lysozyme, (b) 2.5 μg/mL IgG solution containing 20 μg/mL lysozyme, and (c) 2.5 μg/mL mouse IgG.