25th International Meeting on Organic Geochemistry IMOG 2011

P-021
A new solid electrolyte reactor for CF-IRMS analysis of hydrogen
of organic gases and compounds
Eric Galimov 1 , Vyacheslav Sevastyanov 1 , Nataliya Babulevich 2 , Alexander Arzhannikov 1
1 Vernadsky Institute of Geochemistry and Analytical Chemistry, Moscow, Russian Federation, 2 NRC
Kurchatov Institute, Moscow, Russian Federation (corresponding author:vsev@geokhi.ru)
In the past few years, an increase in interest in
oxygen-conducting solid electrolyte has been
observed. The present study is devoted to
development of the high-temperature solid electrolyte
reactor (SER) based on yttria-stabilized zirconia for
water decomposition. Earlier we set up a similar
device for oxidation of organic compounds. The
reduction SER proposed was installed into a system
consisting of HP 6890 capillary chromatograph, a
standard oxidation reactor followed by SER and the
Delta Plus XP isotope ratio mass spectrometer. A
solid electrolyte possesses the oxygen ions related
conductivity at high temperatures (800-1000 o C). This
reactor is made of tubular, thin-walled zirconia
ceramics with inner diameter of 1 mm and of 10 cm
total length. To produce electrodes, both inner and
outer surfaces of this tube were coated by platinum
paste and then annealed in the air. The solidelectrolyte
reactor was connected in three-electrode
circuit. Three-electrode system involved the Elins PS8
Potentiostat. The inner electrode of the reactor served
as the working electrode. Reference electrode was on
the outer side.
After hydrocarbon gases are separated by a GC
column, they are converted into simple gases. The
H2O formed in the oxidation process is decomposed
on the triple-phase interface of the solid electrolyte
reactor. The optimal mode of the solid-electrolyte
reactor operation is the mode that achieving the
complete reduction of water. Oxygen was turned into
ions which under electrical voltage (1.2V) were moved
through solid electrolyte wall outward. The flow of a
He carrier gas swept hydrogen to a Delta Plus XP
isotope ratio mass spectrometer (Thermo Fisher
Scientific). During several seconds compounds
passed through the SER.
A gas mixture in argon (14.8 vol % N2, 6.1 vol % CO2,
9.5 vol % CH4, 6.8 vol % C2H4, 5.6 vol % C3H8, 3.0 vol
% n-C4H10, 7.0 vol % i-C4H10) as well as some other
gases were used for studying. Typically 200 μL gas
mixture (20:1) was injected to HP 6890 GC with
PoraPlot Q column (25 m X 0.32 mm). A GC flow rate
of 1.5 mL/min was used.
We measured δD values of reference natural gas
NIST NGS3 (δD=-176.3 ‰; -175.6 ‰) and obtained
results of δD= -177.2±1.1‰ close to the calibrated
δD values. For the hydrocarbon gas mixture, the
following results were obtained: δD(CH4)= -195.6±1.2
‰, δD(C2H4)=-104.2±1.1 ‰, δD(C3H8)=-110.2±2.7 ‰,
δD(iso-C4H10)=-199.1±0.5 ‰,
δD(n-C4H10)= -173.4±2.3 ‰.
Solid-electrolyte reactors do not require any additional
equipment and extra disposal materials as well. Thus,
the application of a solid-electrolyte in the reduction
reactor design allows to essentially simplify the device
design for δD measurements of hydrocarbons and to
improve its reliability.
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