A High Power Inductively Coupled Plasma Torch and Impedance Matching Network

摘要

The relative ease of operation, power handling capabilities and overall performance of an inductively coupled- plasma-optical emission spectrometer (ICP-OES) depends upon numerous factors, not the least important of which is the design of the torch. A variety of such designs has appeared in the literature. Most workers have employed three concentric fused silica and/or pyrex tubes, referred to as an inner sample gas tube, a 'flaired mouth' plasma gas tube, and an outer coolant tube. These tubes are either fused into one or two-piece units through glass blowing techniques or mounted in some type of dismantleable base assembly. Precise alignment of the glass-blown torch can be achieved during construction through the use of an assembly jig. However, this type of torch in not easily repaired should problems be encountered. The dismantleable base approach can be difficult to align if the three tubes are held only near the bottom. This problem is aggravated by the fact that rarely is commercial quartz and pyrex glass tubing perfectly straight or cylindrical. A torch design which is both dismantleable and self-aligning has been successfully used in this laboratory for several years. A unique feature is the use of nylon or teflon slip fit spacers between the sample and plasma gas tubes and the plasma and coolant gas tubes.