Sample introduction into the inductively coupled plasma by a radiofrequency arc

A new method is described for the introduction of solid samples and liquid-sample residues into the inductively coupled plasma. Unlike earlier such methods, the new technique requires no separate power supply but rather draws its energy from the inductively coupled discharge itself. Termed a radio-frequency arc, the new sampling source carries a current of several amperes from the conventional plasma fireball to a grounded support. Under the tested conditions, the resulting high-frequency arc draws approximately 140 watts from the main discharge and is shown to be adequate to volatilize conductive solids directly or others such as powders or liquid residues which can be placed into or on an inert conductive electrode. In its present form, the sampler operates in an apparently thermal fashion and causes fractional distillation of elements in a sample. Capabilities and limitations of the present arrangement are critically assessed and directions for future work are offered. (Author)