StrippingVoltammetry

Two-step electrochemical measurement in which 1) material is accumulated at an electrode and 2) the amount of an accumulated species is measured by voltammetry. The measured electric current in step 2 is related to the concentration of analyte in the solution by calibration. Anodic stripping voltammetry (ASV) was historically used to measure concentrations of metal ions in solution using cathodic accumulation with mercury to form an amalgam. Due to the toxicity of mercury and its compounds, inductively coupled plasma optical emission spectrometry and inductively coupled plasma mass spectrometry have frequently replaced ASV at mercury electrodes in the laboratory, often sacrificing the probing of speciation and lability in complex matrices. Mercury has now been replaced by non-toxic bismuth or anti- mony as films on a solid electrode support (such as glassy carbon) with equally good sensi- tivity and detection limits. Because the accumulation (pre-concentration) step can be prolonged, increasing the amount of material at the electrode, stripping voltammetry is able to measure very small concentrations of analyte. Often the product of the electrochemical stripping is identical to the analyte before the accumulation. Stripping voltammetry is a calibrated method to establish the relation between amount accumulated in a given time and the concentration of the analyte in solution. Types of stripping voltammetry refer to the kind of accumulation (e.g. adsorptive stripping voltammetry) or the polarity of the stripping electrochemistry (anodic, cathodic stripping voltammetry).