MKF Technologies utilizes the method: Anodic Stripping Voltametry (ASV) for trace metals detection as described in EPA method SW-846 Method 7063. ASV is a voltammetric method for quantitative determination of specific ionic species. The analyte of interest is electroplated on the working electrode during a deposition step, and oxidized from the electrode during the stripping step. The current is measured during the stripping step. The oxidation of species is registered as a peak in the current signal at the potential at which the species begins to be oxidized (Scans below i.e. arsenic)
Anodic stripping voltammetry can detect down to as low as 1 μg/L concentrations of trace metal analytes andhas an excellent detection limit, typically 1ug/L - 100mg/L (with dilution).
The quantification of the unknown metal is determined by using the method of standard addition (MSA), a popular method used in atomic absorption spectroscopy and gas chromatography. By being able to detect analyte's initial signal via ASV, signals of successive additions of known target metal can be recorded to determine the unkown concentration of the sample. The basic steps are as follows: 1) The signal of the unknown target metal is recorded 2) a known amount of the metal of interest is added 3) the sample is analyzed again under the same conditions and the electrical signal is recorded. From the increase in the peak area (or peak height), the original concentration can be computed by extrapolation. Our instrumentation responses are a linear function of analyte concentration and yield no signal (other than background) at zero concentration of the analyte. Below are figures illustrating this method:
Below is a table representing results preformed by the EPA on analysis of arsenic in drinking water detected by methods ASV vs GFAA.
Francis George Thomas; Günter Henze (2001). Introduction to Voltammetric Analysis: Theory and Practice. Csiro Publishing. pp. 58–. ISBN 978-0-643-06593-2.