RAPID-DETERMINATION OF MANGANESE IN SEA-WATER BY FLOW-INJECTION ANALYSIS WITH CHEMILUMINESCENCE DETECTION

Flow-injection analysis (FIA) with chemiluminescence detection was used to determine manganese in sea water. The oxidation of 7,7,8,8-tetracyanoquinodimethane in an alkaline solution produces light. Manganese(II) catalyzes this reaction and its concentration can be determined by measuring the rate of photon emission. A column containing 8-hydroxyquinoline immobilized on a solid support was used in-line in the FIA system to concentrate manganese. The analysis time was 6 min per sea-water sample with a corresponding detection limit of 0.1 nM (3-sigma). Lower detection limits can be obtained by increasing the amount of manganese loaded onto the column. The relative standard deviation of analyses of sea water containing 1-10 nM manganese was typically 3%. Analyses of North Atlantic Surface Sea Water (NASS-1) and Coastal Atlantic Surface Sea Water (CASS-1) standards gave manganese concentrations within the accepted ranges, confirming the accuracy of the technique. Shipboard determinations of manganese produced excellent agreement with previous reliable data. This technique is widely applicable to a variety of natural water and process-oriented studies.