CHARACTERIZATION OF A DIRECT SAMPLE INSERTION DEVICE FOR INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION-SPECTROMETRY

A direct sample insertion device allows insertion of sample carrying probes into an inductively coupled plasma discharge. In this study, analyte emission temporal behavior for such a device was surveyed for several elements with a range of vaporization properties. The emission time behavior for most elements was characterized as a function of probe geometry, composition, insertion speed and insertion position as well as applied plasma power. A long undercut graphite electrode was found to be the best shape for all probe geometries tested. Furthermore, it was demonstrated that the sample carrying probe should be inserted rapidly to a position corresponding to the top of the load coil and the plasma power should be high (1.75-2.00 kW) in order to attain best analytical performance. © 1990.