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Electron Probe Microanalysis of Bromine in Minerals and Glasses with Correction for Spectral Interference from Aluminium, and Comparison with Microbeam Synchrotron X‐Ray Fluorescence Spectrometry
Author(s) -
Zhang Chao,
Lin Jinru,
Pan Yuanming,
Feng Renfei,
Almeev Renat R.,
Holtz Francois
Publication year - 2017
Publication title -
geostandards and geoanalytical research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.037
H-Index - 73
eISSN - 1751-908X
pISSN - 1639-4488
DOI - 10.1111/ggr.12169
Subject(s) - analytical chemistry (journal) , electron microprobe , chemistry , mass spectrometry , synchrotron , microbeam , x ray fluorescence , microanalysis , detection limit , fluorescence , mineralogy , optics , physics , chromatography , organic chemistry
The strong spectral interference between Br‐ and Al‐induced X‐ray lines hampers the utilisation of electron probe microanalysis ( EPMA ) for measuring Br mass fractions in Al‐bearing minerals and glasses. Through measuring Br‐free Al‐bearing materials, we established an EPMA method to quantify the overlap from Al K α on Br L β, which can be expressed as a linear function of the Al 2 O 3 content. The count rate of the Br L β peak signal was enhanced by high beam currents and long measurement times. Application of this EPMA method to Al‐ and Br‐bearing materials, such as sodalite and scapolite, and to five experimental glasses yielded Br mass fractions (in the range of 250–4000 μg g −1 ) that are consistent with those measured by microbeam synchrotron X‐ray fluorescence (μ‐ SXRF ) spectrometry. The EPMA method has an estimated detection limit of ~ 100–300 μg g −1 . We propose that this method is useful for measuring Br mass fractions (hundreds to thousands of μg g −1 ) in Al‐bearing minerals and glasses, including those produced in Br‐doped experiments. In addition, the natural marialitic scapolite ( ON 70) from Mpwapwa (Tanzania) containing homogeneously distributed high mass fractions of Br (2058 ± 56 μg g −1 ) and Cl (1.98 ± 0.03% m/m ) is an ideal reference material for future in situ analyses.