ABSTRACT
This chapter provides an overview of the fundamental principles of ion formation in inductively coupled plasma mass spectrometry — the use of a high-temperature argon plasma to generate positively charged ions. If energy is then applied to the chromium ground-state atom in the form of heat from a plasma discharge, one or more orbiting electrons will be stripped off the outer shell. This will result in only 23 electrons left orbiting the nucleus. Because the atom has lost a negative charge but still has 24 protons in the nucleus, it is converted into an ion with a net positive charge. It still has an atomic mass of 52 and an atomic number of 24, but is now a positively charged ion and not a neutral ground-state atom. In fact, chromium has four naturally occurring isotopes, which means that the chromium atom exists in four different forms, all with the same atomic number of 24, but with different atomic masses.
