A High-Pressure Inductively Coupled Plasma Torch

Abstract

An inductively coupled plasma (ICP) torch utilizing an extended coolant tube that tapers down to a small exit orifice designed to increase the pressure within the ICP torch is described. This torch design makes use of the advantages associated with higher torch operating pressures (including improved detection limits, increased sensitivity, and better plasma stability), without requiring major modifications to existing commercially available ICP torch box and matching networks. Detection limits obtained with the use of the new torch design are compared with those obtained from several commonly used torch designs using a commercially available torch box and spectrometer. A two- to sevenfold improvement in detection limits is observed through increasing torch operating pressure from 101.325 KPa (760 Torr, or atmospheric pressure) to 120 KPa (900 Torr).