LIQUID COOLING OF A TORCH FOR MICROWAVE INDUCED PLASMA SPECTROMETRY

A simple torch design for use with a microwave induced plasma (MIP) is described that can be internally cooled by synthetic or hydrocarbon b ased fluids. The MIP is generated within a liquid coolant-cooled conce ntric quartz discharge torch, energized within a novel microwave plasm a cavity. Erosion of the discharge tube by the plasma, assessed by mea surement of the emission intensity of ablated silicon, is essentially eliminated. The emission spectra of the liquid-cooled plasmas are comp ared to those sustained in uncooled discharge tubes.