Automated Determination of Hydrogen Peroxide at the Micro-Molar Level in Rainwater and Snow Using a Stopped-Flow Approach in a Hybrid Sequential Injection/Flow Injection Manifold

Abstract

A new automated method is reported for the determination of H₂O₂ in real samples. The method is based on the quenching effect of the analyte on the reaction between tris(2-carboxyethyl)phosphine (TCEP) and Ellman's reagent (DTNB). All necessary steps were accomplished under flow conditions using a hybrid sequential injection (SI)/flow injection (FI) setup. The sensitivity was enhanced by applying a stopped-flow step (120 s) in order to promote the reaction between H₂O₂ and TCEP. The proposed analytical protocol was validated for linearity (10–75 µmol L⁻¹), limits of detection (c _L = 1.0 µmol L⁻¹), quantitation (c _Q = 3.3 µmol L⁻¹), precision (s _r = 1.3–1.7%), accuracy, and selectivity. It was then applied successfully to the analysis of H₂O₂ in spiked rainwater and snow samples.

Keywords:

• Ellman's reagent
• Hybrid sequential injection/flow injection
• Hydrogen peroxide
• Stopped-flow
• Tris(2-carboxyethyl) phosphine

Notes

^a Using aqueous solutions.

^b Not detected.

^a Using aqueous solutions.