Rapid and simultaneous analysis of trace metals (Cu, Pb and Cd) in seawater by potentiometric stripping analysis

A potentiometric stripping method for a simultaneous measurement of copper, lead and cadmium in oceanic waters using a TraceLab PSU22 unit has been developed. Compared to the earlier TraceLab PSU20 unit, the PSU22 has a sampling rate of the potential during the stripping step that is three times lower. This results in the decrease of the detection limit by about four times. The detection limits obtained with a pre-electrolysis time of 15 min were 44 ng l−1 (0.7 nM), 3 ng l−1 (14 pM) and 1 ng l−1 (9 pM) for Cu, Pb and Cd, respectively. The precision, accuracy and reproducibility of the method agree well with those obtained by other techniques for trace metals analysis in seawater. Vertical profiles of Cd in the Mediterranean waters obtained by AA and PSA were concordant.