COMPARISON OF AXIALLY AND RADIALLY VIEWED INDUCTIVELY-COUPLED PLASMA-ATOMIC EMISSION-SPECTROMETRY IN TERMS OF SIGNAL-TO-BACKGROUND RATIO AND MATRIX EFFECTS - PLENARY LECTURE

A comparison was made of axial and radial viewing modes in terms of th e signal-to-background ratio for several commercially available ICP-AE S systems. The average improvement factor was found to be in the range of 2-3 for ionic lines when the axial viewing mode was used. To obtai n higher improvement factors, other modifications of the ICP systems m ust be associated with axial viewing, such as better practical resolut ion of the dispersive system and better efficiency of the sample intro duction system. Matrix effects with axial viewing, such as those resul ting from the presence of Na, can be minimized to the same extent as f or radial viewing provided that a high rf power and a low carrier gas how rate are used to optimize the exchange of energy between the surro unding plasma and the central channel. An increase in the id of the to rch injector is also beneficial for this purpose.