Voltammetric Monitoring of Bivalent Iron in Waters and Effluents, using a Dental Amalgam Sensor Electrode. Some Preliminary Results

A very sensitive method for detection of iron (II) in the ng/L rage with a deposition time of 180 s by use of differential pulse anodic stripping voltammetry on the novel dental amalgam electrode is introduced and tested in different supporting media. A well-defined peak for the oxidation of iron metal to ferrous ion was observed around � 750 mV in citrate, oxalate and nitrate solutions. Good linearity has been found (r2avg = 0,998) for different concentration ranges. The deposition had to be performed at a potential lower than � 1050 mV. At deposition potentials more positive than this, the iron peak was absent in the stripping step, making it possible to measure iron independent of lead and cadmium by use of subtractive stripping. Measurements of real samples from river and seawater without any significant change in the pH are demonstrated. The use of this stable and non-toxic electrode together with the unique sensitivity makes the reported system suitable for implementation in continuous monitoring systems for online detection of iron in rivers and in seawater.