ABSTRACT
This chapter looks at the inductively coupled plasma mass spectrometry (ICP-MS) interface region, which is probably the most critical area of the entire ICP-MS system. It is therefore clear that maintaining neutral plasma is of paramount importance to guarantee the electrical integrity of the ion beam as it passes through the interface region. The coupling of the plasma to the mass spectrometer proved to be very problematic during the early development of ICP-MS because of an undesirable electrostatic coupling between the voltage on the load coil and the plasma discharge, producing a potential difference of 100–200 V. Although this potential is a physical characteristic of all ICP discharges, it was more serious in an ICP mass spectrometer, because the capacitive coupling created an electrical discharge between the plasma and the sampler cone. The impact of a secondary discharge cannot be overemphasized with respect to its effect on the kinetic energy of the ions being sampled.
