Rapid and selective determination of hydrogen peroxide residues in milk by batch injection analysis with amperometric detection

We report a highly rapid, precise, selective and sensitive analytical method for the determination of hydrogen peroxide in milk using a batch-injection analysis (BIA) with amperometric detection at a Prussian-blue bulk modified graphite-composite electrode. An electronic micropipette injected 100 μL aliquots of 10-fold diluted samples (high and low-fat milk) directly onto the modified electrode immersed in the BIA cell. The analytical features of our proposed method includes low RSD between injections (0.76%, n = 9), low detection limit (10 μmol L−1), elevated analytical frequency (up to 80 h−1) and satisfactory recovery values for spiked samples. A fresh and highly reproductive electrode surface can be easily obtained by simple mechanical polishing (RSD = 1.6%, n = 5). The storage stability of the PB-modified graphite-composite surpassed 1 year keeping equivalent performance as initially presented. The association of BIA with an improved amperometric detector provides great promise for routine monitoring of hydrogen peroxide in milk and other beverages.