Determining the Copper-Complexing Capacity of Known Organic Compounds and Soluble Organic Matter in Natural Waters by Differential Pulse Anodic Stripping Voltammetry Peak-Potential Shift

摘要

A new method for determining the copper-complexing capacity of known organic compounds in distilled water and soluble organic matter in natural aquatic systems is reported. This method is based on the differential pulse anodic stripping peak potential shift. The complexing capacity in natural waters thus determined is a measure of copper complexation upon the addition of the metal; it does not include copper already complexed. We found complexing capacities for glycine at pH 6.8 and nitrilotriacetic acid (NTA) at pH 6.8 in distilled water to be 4.31 x 10 exp -2 mol Cu/mol glycine and 1.01 mol Cu/mol NTA, respectively. Complexing capacity results from natural freshwater at pH 4.5, 2.00 x 10 exp -6 M Cu, and from natural seawater at pH 7.6, 295 x 10 exp -8 M Cu, as well as theoretical considerations and methodology are discussed. (ERA citation 04:034359)