Gas phase sample injection

Abstract

In principle the introduction of sample material in the gas phase is an ideal technique for the ICP. It would be widely practised if methods were available by which large suites of elements could be volatilized in a manner which was both convenient and compatible with ICP instrumentation. The principal benefits of vapour phase injection are (a) the avoidance of the use of a nebulizer, which is a major cause of problems in ICP-AES, and which sets a limit to the salt content of the test solution; (b) the potential for 100% efficiency of injection compared with a maximum of about 2–5% obtainable with a pneumatic nebulizer; and (c) the injection of a homogeneous medium into the plasma, which demands a lower power input to achieve complete atomization of the sample. Unfortunately few such gas phase injection systems have been proposed and, indeed, few are even conceivable which would operate at normal laboratory temperatures for a reasonably large suite of elements.