ICP

With ICP (inductively coupled plasma) analysis, it is possible to get results on trace elements and heavy metal contamination at a reasonable price, even for the layman.

Function:
Temperatures of 6000...12000°C are present in a generated argon plasma. At these conditions, almost all sample components injected into the plasma decay to ionized (charged) atoms. These can be analyzed by two different methods.
ICP-OES = inductively coupled plasma - optical emission spectrometry: The generated ionized atoms are analyzed based on their optical emission spectrum. When the ionized (excited) atoms fall back to their normal state, they emit a specific color of light.
ICP-MS = inductively coupled plasma - mass spectrometry: The generated ionized atoms are "sorted" and detected ("counted") based on their mass ("weight") in a magnetic field. Even the different isotopes can be measured.
ICP-MS is more complex, but smaller amounts can be detected.

What can an ICP not measure?
Because nitrogen is dissolved in water, no statements can be made about the aquaristically important nitrogen compounds. Additional photometer measurements are necessary.
It is also not possible to distinguish whether the atoms measured originate from inorganic or organic compounds. Phosphorus in particular is present as inorganic phosphate and organically bound in many important compounds.