DETERMINATION OF HYDROGEN-PEROXIDE IN SEA-WATER BY FLOW-INJECTION ANALYSIS WITH CHEMILUMINESCENCE DETECTION

Hydrogen peroxide (H2O2) 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 H2O2 in sea water is reported. It is based on the H2O2 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 mu l) 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 H2O2 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 H2O2 is presented.