Voltammetric determination of trace mercury in concentrated chloride mediausing polymer-film electrodes modified with polyammonium macrocyclic receptors

Trace amounts of mercury can be determined voltammetrically in aqueous solu tion on Paraloid B72 film electrodes modified by the macrocyclic polyamine receptors 1,4,7,10,13,16,19,22,25,28-decaazacyclotriacontane and 1,4,7,10,1 3,16,19,22,25,28,31-undecaazacyclotritriacontane. These receptors are able to form very stable mono-, bi-, and trinuclear complexes with Hg2+ ions in the pH range 3-12, favouring the preconcentration step. Very stable Cl--mac rocycle mixed complexes with Hg2+ are also formed, allowing the determinati on of mercury traces in large concentrated chloride media. Under optimized conditions, this procedure gives good linearity for nanomolar mercury conce ntrations and a detection limit of 0.2 x 10(-10) mol L-1. Results concernin g the optimization of the method and lowering of the influence of possible interferents are reported.