Pl. Croot et M. Johansson, Determination of iron speciation by cathodic stripping voltammetry in seawater using the competing ligand 2-(2-thiazolylazo)-p-cresol (TAC), ELECTROANAL, 12(8), 2000, pp. 565-576
A new sensitive competitive ligand exchange-adsorptive cathodic stripping v
oltammetric (CLE-ACSV) method for the determination of iron speciation in s
eawater has been developed using the iron binding ligand TAC 2-(2-thiazolyl
azo)-p-cresol. An earlier method for determining iron using TAC [1] was ree
xamined and optimized for measurements in seawater at pH 8.0. The sensitivi
ty was improved by employing a fast (10.12 V/s) linear sweep scan waveform.
The detection limit (3 sigma of blank) is 0.10 nM after an adsorption time
of 300 s; the detection limit can be lowered, however, by using a longer d
eposition time or for the determination of total iron, by increasing the pH
to 8.5. This method was applied to samples from Swedish coastal waters and
the results indicate the possible efflux of iron binding ligands from sedi
ments in coastal waters.