Interference study. Current–time response plot of AgNP-NH2-SBA-15-GCE (electrode composition C4, Section 2.5) for H2O2 (50 μM) in presence of reducible (sodium nitrate, sodium nitrate) and oxidizable (urea, glucose, ascorbic acid) interfering species each with 2.4 mM concentration. Conditions: applied potential −0.4 V (vs. SCE), 20 ml of N2 saturated buffer solution of pH 7.