Inductively coupled plasma mass spectrometry (ICP-MS)

Inductively coupled plasma mass spectrometry, or ICP-MS, is a highly sensitive method for measuring individual elements, used mainly for heavy metal testing.

The sample is digested in acid, sprayed into an argon plasma hot enough to break it into charged atoms, and the mass spectrometer counts atoms of each element by mass. It can detect metals at parts-per-billion levels and measure many elements in a single run. That sensitivity is why it is the usual method behind the heavy metals section of a certificate of analysis.

Reading the result means looking at the measured value for each element next to its action limit and the method's limit of quantitation. A value reported as below the quantitation limit means the instrument could not assign a reliable number at that level, which is a statement about the method's floor rather than proof of absence. The method identifies elements only; it says nothing about pesticides, solvents or cannabinoids, which require separate tests.