Investigation of plasma-related matrix effects in inductively coupled plasma-atomic emission spectrometry caused by matrices with low second ionization potentials - identification of the secondary factor

被引:52
作者
Chan, George C. -Y. [1 ]
Hieftje, Gary M. [1 ]
机构
[1] Indiana Univ, Dept Chem, Bloomington, IN 47405 USA
关键词
matrix effects; second ionization; inductively coupled plasma-atomic emission spectrometry; penning ionization; energy levels;
D O I
10.1016/j.sab.2005.09.007
中图分类号
O433 [光谱学];
学科分类号
0703 ; 070302 ;
摘要
Plasma-related matrix effects induced by a comprehensive list of matrix elements (a total of fifty-one matrices) in inductively coupled plasmaatomic emission spectrometry were investigated and used to confirm that matrix effects caused by elements with a low second ionization potential are more severe than those from matrix elements having a low first ionization potential. Although the matrix effect is correlated unambiguously with the second ionization potential of a matrix, the correlation is not monotonic, which suggests that at least one other factor is operative. Through study of a large pool of matrix elements, it becomes possible to identify another critical parameter that defines the magnitude of the matrix effect; namely the presence of low-lying energy levels in the doubly charged matrix ion. Penning ionization by Ar excited states is proposed as the dominant mechanism for both analyte ionization/excitation and matrix effects; matrices with a low second ionization potential can effectively quench the population of Ar excited states through successive Penning ionization followed by ion-electron recombination and lead to more severe matrix effects. (c) 2005 Elsevier B.V. All rights reserved.
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页码:642 / 659
页数:18
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