Interference Effects from Easily Ionizable Elements in Flame AES and ICP‐OES: A Proposed Simplified Rate Model Based on Collisional Charge Transfer Between Analyte and Interferent Species

Abstract

The effects of excess Na and K on K and Mg atom line emission in the airacetylene flame and of excess Li and K on Ca, Mg, and Sr atom and ion lines in inductively coupled plasma spectroscopy were studied using emission signal ratios, I 0 /I as probes, where I 0 and I are the emission readings in the presence and absence of the interferent respectively. The I 0 /I plots as a function of analyte concentration in the test solution for the ICP experiments were similar to those obtained for the flame experiments in the analytical range 0 -10 mg/L. A simplified rate model based on analyte excitation via charge transfer between analyte ions and activated interferent atoms is proposed to account for the emission signal enhancement observed at low analyte concentrations (,1 mg/L) for both ICP-AES and flame atomic emission spectroscopy (AES). Data are presented showing good agreement between experimental E 0 calibration curves and theoretical E 0 calibration curves computed using the simplified rate model.

Departure from local thermal equilibrium during ICP-AES and FAES: Characterization in terms of collisional radiative recombination activation energy

“…The experimental procedure adopted was described previously [55][56][57]. Two sets of standard solutions containing 0 to 30.0 mg/L analyte (Mg, Ca, Sr, and K) were prepared from freshly prepared solutions of their chloride salt.…”

“…To date there is no satisfactory explanation for this departure of the ICP from LTE. Zaranyika et al [56] demonstrated the similarity between emission signal enhancement profiles in the ICP and air-acetylene flame, see Fig. 1, prompting the authors to suggest that the effects of EIEs are entirely due to the presence of the interferent, and that the differences in the temperature and composition of the ICP and those of the air-acetylene flame are not significant as far as emission signal enhancement is concerned.…”

Trace Element Determination by ICP‐AES and ICP‐MS: Developments and Applications Reported During 2006 and 2007

“…As expected, changes in plasma parameters observed for the different nebulisers were related to plasma solvent load. The effects of excess K and Li on Ca, Mg and Sr atom and ion lines in ICP-AES was also studied using ratios of emission signal readings in the presence and absence of the interferents (Zaranyika et al 2007). Ratios from ICP-AES experiments were similar to those obtained for air-acetylene flame AES experiments between 0-10 mg l -1 , suggesting that Ar ionisation did not influence the enhancement, and that collisional charge transfer between the analyte and interferent species was significant.…”

Plasma Diagnostics through Kinetic Modelling: Characterization of Matrix Effects during ICP and Flame Atomic Spectrometry in terms of Collisional Radiative Recombination Activation Energy?A Review

“…Two approaches have been proposed: (a) correlation of analyte emission with localized concentration maps of the analyte in the absence and presence of interferent species (Hieftje et al [19,52,53]), and (b) theoretical simulation of the signal enhancement ratio in the analytical zone of the plasma in the presence of EIEs [56][57][58][59][60].…”