Heavy Metals

What it determines

A weighed portion of sample is digested in acid until the organic matrix is destroyed and every element is carried into solution. The digest is nebulized into an argon plasma hot enough to strip electrons from the atoms, producing a stream of ions.

The mass analyzer separates those ions by mass-to-charge ratio and counts them. Concentrations are calculated against calibration standards for each element. The output is a mass fraction for every element on the method's list.

Practical notes

• Containers contribute. Metal-capped vials, some stoppers, and unlined closures can add trace elements to the material they hold, and that shows up in the result.
• Digestion consumes the aliquot, so this assay draws its own portion of the sample.