SPECIATION OF TRACE-METALS IN SEAWATER BY ANODIC-STRIPPING VOLTAMMETRY - CRITICAL ANALYTICAL STEPS

The speciation of trace metals in seawater based on the voltammetric ( DPASV) titration of ligands by metal addition is considered. The metho d allows the determination of the total metal amount, the ''labile'' f raction, the ligand concentration and the related conditional stabilit y constant. Analytical problems related to sample contaminations durin g sampling, filtration and storage, displacement of complexing equilib ria in freeze storage, the kinetics of the reaction of complexation an d the potential kinetic lability of organic complexes are discussed an d possible solutions presented. Data on quality control tests carried out to verify the accuracy of the laboratory procedure for trace metal determination in seawater are reported.