Determination of labile iron at low nmol L-1 levels in estuarine and coastal waters by anodic stripping voltammetry

A new method is presented for the determination of electrochemically labile iron in estuarine and coastal seawater. The method is based on differential pulse anodic stripping voltammetry (DPASV) at a rotating silver-alloy disk electrode. The voltammetric parameters include a plating potential of -1.5 V and an activation potential of -5 V for 10s; the seawater is at the original sample pH. The main finding is the presence of a peak for low nmol L-1 levels of iron at -0.55 V ascribed to elemental iron deposited on the bare silver alloy electrode. The peak increased linearly with the iron concentration between