Formation and suppression of AlF3 during HF digestion of rock samples in Teflon bomb for precise trace element analyses by ICP-MS and ID-TIMS

Hiroyuki Takei, Tetsuya Yokoyama, Akio Makishima, Eizou Nakamura

Research output: Contribution to journalArticle

37 Citations (Scopus)

Abstract

An aluminum fluoride, AlF3, forms during HF digestion of felsic rock samples, for trace element and isotope geochemistry, which use a Teflon bomb at high temperature and pressure. The AlF3 incorporates trace elements (Rb, Sr, Y, Cs, Ba, REE, Pb, Th, and U), and can not be decomposed by conventional methods such as evaporation with HClO4. The production of this AlF3 results in lower yields and poor accuracy in analyses of these trace elements by ICP-MS. The formation of AlF3 is controlled by the chemical composition of the rock samples, in particular, AlF3 does not form during decomposition of mafic samples with relatively high (Mg+Ca)/Al ratios. We have developed a new method to suppress the AlF3 formation, in which excess Mg is added to the sample prior to acid digestion in the bomb. This new method makes it possible to accurately determine the trace element compositions of higher-Al rock samples with lower concentrations of Mg and Ca (e.g. rhyolite and granite). In the trace element analyses by TIMS with isotope dilution techniques (ID-TIMS), AlF3 formation hinders the achievement of isotope equilibrium, resulting in erroneous results. However, the Mg-addition method removed this problem by suppression of AlF3 formation.

Original languageEnglish
Pages (from-to)13-17
Number of pages5
JournalProceedings of the Japan Academy Series B: Physical and Biological Sciences
Volume77
Issue number1
Publication statusPublished - Jan 2001

Fingerprint

Bombs
inductively coupled plasma mass spectrometry
teflon (trademark)
Polytetrafluoroethylene
Trace Elements
trace elements
Digestion
rocks
digestion
retarding
Isotopes
isotopes
sampling
aluminum fluorides
Indicator Dilution Techniques
rhyolite
isotope dilution technique
granite
geochemistry
fluorides

Keywords

  • AlF
  • Felsic rock
  • HF digestion
  • Teflon bomb
  • Trace elements

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • General

Cite this

@article{ce253fe831aa4cf0afd83a51f73426dd,
title = "Formation and suppression of AlF3 during HF digestion of rock samples in Teflon bomb for precise trace element analyses by ICP-MS and ID-TIMS",
abstract = "An aluminum fluoride, AlF3, forms during HF digestion of felsic rock samples, for trace element and isotope geochemistry, which use a Teflon bomb at high temperature and pressure. The AlF3 incorporates trace elements (Rb, Sr, Y, Cs, Ba, REE, Pb, Th, and U), and can not be decomposed by conventional methods such as evaporation with HClO4. The production of this AlF3 results in lower yields and poor accuracy in analyses of these trace elements by ICP-MS. The formation of AlF3 is controlled by the chemical composition of the rock samples, in particular, AlF3 does not form during decomposition of mafic samples with relatively high (Mg+Ca)/Al ratios. We have developed a new method to suppress the AlF3 formation, in which excess Mg is added to the sample prior to acid digestion in the bomb. This new method makes it possible to accurately determine the trace element compositions of higher-Al rock samples with lower concentrations of Mg and Ca (e.g. rhyolite and granite). In the trace element analyses by TIMS with isotope dilution techniques (ID-TIMS), AlF3 formation hinders the achievement of isotope equilibrium, resulting in erroneous results. However, the Mg-addition method removed this problem by suppression of AlF3 formation.",
keywords = "AlF, Felsic rock, HF digestion, Teflon bomb, Trace elements",
author = "Hiroyuki Takei and Tetsuya Yokoyama and Akio Makishima and Eizou Nakamura",
year = "2001",
month = "1",
language = "English",
volume = "77",
pages = "13--17",
journal = "Proceedings of the Japan Academy Series B: Physical and Biological Sciences",
issn = "0386-2208",
publisher = "Japan Academy",
number = "1",

}

TY - JOUR

T1 - Formation and suppression of AlF3 during HF digestion of rock samples in Teflon bomb for precise trace element analyses by ICP-MS and ID-TIMS

AU - Takei, Hiroyuki

AU - Yokoyama, Tetsuya

AU - Makishima, Akio

AU - Nakamura, Eizou

PY - 2001/1

Y1 - 2001/1

N2 - An aluminum fluoride, AlF3, forms during HF digestion of felsic rock samples, for trace element and isotope geochemistry, which use a Teflon bomb at high temperature and pressure. The AlF3 incorporates trace elements (Rb, Sr, Y, Cs, Ba, REE, Pb, Th, and U), and can not be decomposed by conventional methods such as evaporation with HClO4. The production of this AlF3 results in lower yields and poor accuracy in analyses of these trace elements by ICP-MS. The formation of AlF3 is controlled by the chemical composition of the rock samples, in particular, AlF3 does not form during decomposition of mafic samples with relatively high (Mg+Ca)/Al ratios. We have developed a new method to suppress the AlF3 formation, in which excess Mg is added to the sample prior to acid digestion in the bomb. This new method makes it possible to accurately determine the trace element compositions of higher-Al rock samples with lower concentrations of Mg and Ca (e.g. rhyolite and granite). In the trace element analyses by TIMS with isotope dilution techniques (ID-TIMS), AlF3 formation hinders the achievement of isotope equilibrium, resulting in erroneous results. However, the Mg-addition method removed this problem by suppression of AlF3 formation.

AB - An aluminum fluoride, AlF3, forms during HF digestion of felsic rock samples, for trace element and isotope geochemistry, which use a Teflon bomb at high temperature and pressure. The AlF3 incorporates trace elements (Rb, Sr, Y, Cs, Ba, REE, Pb, Th, and U), and can not be decomposed by conventional methods such as evaporation with HClO4. The production of this AlF3 results in lower yields and poor accuracy in analyses of these trace elements by ICP-MS. The formation of AlF3 is controlled by the chemical composition of the rock samples, in particular, AlF3 does not form during decomposition of mafic samples with relatively high (Mg+Ca)/Al ratios. We have developed a new method to suppress the AlF3 formation, in which excess Mg is added to the sample prior to acid digestion in the bomb. This new method makes it possible to accurately determine the trace element compositions of higher-Al rock samples with lower concentrations of Mg and Ca (e.g. rhyolite and granite). In the trace element analyses by TIMS with isotope dilution techniques (ID-TIMS), AlF3 formation hinders the achievement of isotope equilibrium, resulting in erroneous results. However, the Mg-addition method removed this problem by suppression of AlF3 formation.

KW - AlF

KW - Felsic rock

KW - HF digestion

KW - Teflon bomb

KW - Trace elements

UR - http://www.scopus.com/inward/record.url?scp=23044525180&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=23044525180&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:23044525180

VL - 77

SP - 13

EP - 17

JO - Proceedings of the Japan Academy Series B: Physical and Biological Sciences

JF - Proceedings of the Japan Academy Series B: Physical and Biological Sciences

SN - 0386-2208

IS - 1

ER -