Effect of radiofrequency power on laser induced fluorescence and emission spectrometry with an extended-sleeve inductively-coupled plasma torch

Abstract

Relative laser-excited fluorescence and emission intensities as a function of RF power were measured for the Ca-I, Ca-II, Ba-I, Ba-II, Mg-I, Mg-H, Na-I and Cu-I lines with an extended inductively-coupled plasma (ICP) torch. In most cases, the relationships were different from those found in previous studies with a conventional short ICP torch. In some cases, unexpected double maxima or minima occurred. A study of the effect of an easily ionized element, potassium, on the fluorescence at the Ca-I and Ca-II lines with the extended-sleeve torch showed a considerably larger ionization interference than exists with the conventional short torch. The extended torch has found some use in laser-excited fluorescence and ICP-excited fluorescence, but researchers should be wary of unexpected variations with power and substantial ionization interferences.