Determination of hydrogen peroxide in sea water by flow-injection analysis with chemiluminescence detection

Abstract

Hydrogen peroxide (H 2O 2) plays a key role in many marine chemical processes, e.g., redox reactions involving transition metals and organic compounds. A rapid, flow-injection procedure with chemiluminescence detection for the determination of H 2O 2 in sea water is reported. It is based on the H 2O 2 induced oxidation of an alkaline solution of luminol in the presence of a catalyst (cobalt(II)). The sample throughput was 120 h −1 with small sample volumes (100 μ1) and low detection limits (10 nM in Milli-Q water; 5 nM in sea water, S N = 3 ). The working linear range, which is suitable for the determination of ambient levels of H 2O 2 in sea water was 5–500 nM. A portable, automated version of the monitor has been successfully deployed onboard ship in the western Mediterranean and a typical depth profile for H 2O 2 is presented.