TY - JOUR

T1 - 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

AU - Zhang, Chao

AU - Lin, Jinru

AU - Pan, Yuanming

AU - Feng, Renfei

AU - Almeev, Renat R.

AU - Holtz, Francois

N1 - Funding information: We thank two anonymous journal reviewers for helpful comments and Kathryn Linge for editorial handling. We also thank Prof. Jürgen Koepke (LUH) for inspiring discussions. This study was supported by a ‘Wege in die Forschung’ project (granted by Leibniz Universität Hannover to Chao Zhang) and DFG (German Research Foundation) project BE 1720/40.

PY - 2017/9

Y1 - 2017/9

N2 - 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 AlKα on BrLβ, which can be expressed as a linear function of the Al2O3 content. The count rate of the BrLβ 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 (ON70) 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.

AB - 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 AlKα on BrLβ, which can be expressed as a linear function of the Al2O3 content. The count rate of the BrLβ 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 (ON70) 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.

KW - aluminium

KW - bromine

KW - electron probe microanalysis

KW - interference

KW - synchrotron X-ray fluorescence spectrometry

UR - http://www.scopus.com/inward/record.url?scp=85017546429&partnerID=8YFLogxK

U2 - 10.1111/ggr.12169

DO - 10.1111/ggr.12169

M3 - Article

AN - SCOPUS:85017546429

VL - 41

SP - 449

EP - 457

JO - Geostandards and Geoanalytical Research

JF - Geostandards and Geoanalytical Research

SN - 1639-4488

IS - 3

ER -