EFFECT OF EASILY IONIZABLE ELEMENTS ON SOLUTIONS AND SLURRIES IN AN AXIALLY VIEWED INDUCTIVELY-COUPLED PLASMA

A Perkin-Elmer Optima 3000 axially viewed ICP spectrometer was used to study the effects of EIEs on the spatially dependent ion and atom emi ssion intensities from Mg containing solutions and slurries, Using the Mg 279.553 nm ion and 285.213 nm atom line emission profiles, ion:ato m emission intensity ratios were measured, with and without EIEs, acro ss the plasma to visualize the changes in energy transfer processes wh en an EIE is present, Transport effects are negated when this ion:atom /ion:atom ratio is employed, In the presence of an EIE, both atom line ratios and ion line ratios are enhanced for solutions and slurries an d this enhancement increases in the order Li < Na less than or equal t o K < Cs. Profiles of ion(EIE):ion and atom(EIE):atom ratios show grea ter enhancement for the excited ion population than the excited atom p opulation, This indicates an increased departure from simple 'Saha' LT E conditions for both solutions and slurries with EIEs, While similar energy transfer processes are seen for solutions and slurries, under t hese matrix conditions, the magnitude of the enhancement in slurries i s less than that of solutions when Li and Na are present, A reduced at omization efficiency for slurries relative to the matrix-matched solut ions is implied. This relative atomization efficiency is seen to chang e for different systems. A refractory MgO slurry, which contained part icles up to 4 mu m in diameter, gave a relative atomization efficiency of 80-85% in the absence of an EIE. In the presence of an EIE, the re lative efficiency increased up to 100% in the order Li < Na approximat e to K approximate to Cs. This effect may be attributed to (i) a 'real ' increase in atomization efficiency, (ii) subtle changes in the rejec tion of a larger solid particle fraction or (iii) a combination of bot h, Atom line ratio profiles show spatially dependent structure, simila r to a 'caldera', when EIEs are present. The rim of this atom caldera is the interface between the central analyte channel and the plasma bo dy. These profiles allow the energy transfer processes that occur in t his region to be visualized. The presence of EIEs causes this region t o be enhanced and increase in the order, Li < Na less than or equal to K < Cs. Ion line profiles are relatively flatter, Ion:atom ratio prof iles show that an energy transfer process involving ion population enh ancement occurs at the centre of the analyte channel when an EIE is pr esent.