Which action best prevents electrode malfunction in samples with high protein content?

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Protein fouling is the main issue when samples are rich in protein—the proteins can rapidly adsorb onto the electrode surface, blocking active sites and hindering electron transfer, which leads to unstable or degraded signals. The best way to prevent this is to actively remove the protein layer: using a proteolytic enzyme like pepsin digests proteins into smaller fragments that are easier to wash away, while bleach oxidizes residual organic matter, and an acidic environment (such as 0.1 M HCl) helps solubilize and detach protein fragments from the surface. This combination directly targets the fouling layer and helps restore stable, reliable electrode performance. Cleaning inorganic deposits with EDTA targets minerals and salts, not proteins, so it won’t address protein fouling. Maintaining temperature helps with reaction conditions but doesn’t remove the existing protein film, and wiping with a dry cloth can smear or leave behind contamination rather than clean the surface.