Specifically triggered dissociation based ratiometric electrochemical sensor for H₂O₂ measurement in food samples

A novel ratiometric strategy based electrochemical sensor was developed to quantitative assay of H₂O₂ in different food samples. 4-aminophenylboronic acid pinacol ester (ABAPE) dissociation was specifically triggered by H₂O₂ to generate electro-active 4-aminophenol (4-AP), which not only can be oxidized to indirectly indicate the concentration of H₂O₂, but also endowed the sensor with high selectivity. Meanwhile, a reference probe of poly(thionine) (TH) was modified with ketjen black (KB) and gold nanoparticles (AuNPs) on electrode surface. KB and AuNPs displayed high electrocatalytic activity to 4-AP. A current ratio between 4-AP and TH (i/i_TH) showed a good linear relationship with the concentration of H₂O₂ in a range of 3.0 × 10^-7 - 1.0 × 10^-4 mol/L (0.010 ppm - 3.40 ppm) with a limit of detection of 2.6 × 10^-7 mol/L (0.009 ppm) (S/N = 3). Moreover, the ratiometric strategy based sensor possessed good accuracy, reliability, and stability, and successfully determined H₂O₂ in food samples with satisfactory results.