Fast batch injection analysis of H2O2 using an array of Pt-modified gold microelectrodes obtained from split electronic chips

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Analytica Chimica Acta
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Pacheco B.D.
Valerio J.
Angnes L.
Pedrotti J.J.
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A fast and robust analytical method for amperometric determination of hydrogen peroxide (H2O2) based on batch injection analysis (BIA) on an array of gold microelectrodes modified with platinum is proposed. The gold microelectrode array (n=14) was obtained from electronic chips developed for surface mounted device technology (SMD), whose size offers advantages to adapt them in batch cells. The effect of the dispensing rate, volume injected, distance between the platinum microelectrodes and the pipette tip, as well as the volume of solution in the cell on the analytical response were evaluated. The method allows the H2O2 amperometric determination in the concentration range from 0.8μmolL-1 to 100μmolL-1. The analytical frequency can attain 300 determinations per hour and the detection limit was estimated in 0.34μmolL-1 (3σ). The anodic current peaks obtained after a series of 23 successive injections of 50μL of 25μmolL-1 H2O2 showed an RSD<0.9%. To ensure the good selectivity to detect H2O2, its determination was performed in a differential mode, with selective destruction of the H2O2 with catalase in 10mmolL-1 phosphate buffer solution. Practical application of the analytical procedure involved H2O2 determination in rainwater of São Paulo City. A comparison of the results obtained by the proposed amperometric method with another one which combines flow injection analysis (FIA) with spectrophotometric detection showed good agreement. © 2011 Elsevier B.V.
Assuntos Scopus
Amperometric determination , Amperometry , Batch-injection analysis , Gold microelectrodes , Phosphate buffer solutions , Rainwater , Robust analytical methods , Spectrophotometric detection
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