HIGH-POWER (0.4-1.2 KW) ARGON SURFACE-WAVE PLASMA FOR LIQUID SOLUTIONANALYSIS

Argon surface-wave plasmas produced at power ranging from 0.5 to 1.2 k W are sustained at atmospheric pressure for the study of direct aqueou s solution introduction. The plasmas are generally operated at 2450 MH z, but some results are also obtained for a 400 W 27 MHz surface-wave plasma. The emission spectra have been studied between 220 and 940 nn with a medium-resolution spectrometer and with an intensified photodio de array as detector. The effect of the operating parameters (gas dow rate, power) on intensity and signal-to-background noise ratio has bee n investigated for selected analytes. The detection limits were determ ined for several analytes (Ba, Ca, Cu, Cr, and Zn) and were found to b e comparable to the detection limits obtained with other microwave-ind uced plasmas.