Dear Julie,

Br isotope measurement is a rare practice... But some studies exist, as I
can extract from the chapter on Cl and Br isotope analytical methods in my
books by my friend Hans Eggenkamp. Some references are:

gas source IRMS:
Eggenkamp H. G. M. and Coleman M. L. (2000) The application of classical
methods for the measurement of stable bromine isotopes in natural samples.
Chem. Geol. 167, 393-402.

Willey J. F. and Taylor J. W. (1978) Capacitive integration to produce
high-precision isotope ratio measurements on methyl chloride and methyl
bromide samples. Anal. Chem. 50, 1930-1933.

negative TIMS:
Cameron A. E. and Lippert E. L. J. (1955) Isotopic composition of bromine in
nature. Science 121, 136-137.

Cameron A. E., Herr W., Herzog W., and Lundén A. (1956)
Isotopen-Anreicherung beim Brom durch electrolytische Überführung in
geschmolzenem Bleibromid. Z. Naturforsch. 11a, 203-205.

Lundén A. and Lodding A. (1960) Isotopenanreicherung bei Brom durch
electrolytische Überführung in geschmolzenem Zinkbromid. Z. Naturforsch.
15a, 320-322.

positive TIMS:
Xiao Y.-K., Liu W.-G., Qi H.-P., and Zhang C.-G. (1993) A new method for the
high-precision isotopic measurement of bromine by thermal ionization
mass-spectrometry. Int. J. Mass Spectrom. Ion Proc. 123, 117-123.

ICP-MS:
D'Allessandro M., Bidoglio G., Mousty F., Sala Benito J. V., and Yllera De
Llano A. (1997) Laboratory and in situ investigation of the isotopic ratio
79Br/81Br as a tracer of water migration in crystalline rocks. J. Hydrol.
193, 351-362.

Janghorbani M., Davis T. A., and Ting B. T. G. (1988) Measurement of stable
isotopes of bromine in biological fluids with inductively coupled plasma
mass spectrometry. Analyst 113, 405-411.

Nirel P. M. V. and Lutz T. M. (1991) Plasma-source mass spectrometry
(ICP-MS) application to multi-element analysis in environmental samples, a
practical evaluation. J. Trace Microprobe Techn. 9, 95-106.

Not all of these studies are on hydrological subjects, but it might help to
give you an idea about some existing methods. At least one Br-isotope study
on groundwater is included here!

Best wishes,
Pier.

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Dr. Pier A. de Groot
Pastoor Moorkensstraat 16
2400 Mol - Achterbos
Belgium
Tel. +32 (0)14 326 205
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Visit my WEB-site about my ³Handbook of Stable Isotope Analytical
Techniques² at:
http://users.pandora.be/handbook/index.html
last update: 9 March, 2003.
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