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Oxy-Anion Stable Isotope Consortium (OASIC)

OASIC Hall of Fame (2007)

Current members:
  Justin Hayles, Bryan Killingsworth, Dustin Boyd, Madison Kymes, Changjie Liu, Adam Bao, and Huiming Bao

Past members and visitors:
   Issaku Kohl, Yongbo Peng, Tao Sun , Xiaoqian Li, Margarita Khachaturyan, Katy Jenkins, Katie Howell, Chee-Haur Siew, Tao Fang, Katie Bourgeois, Zhi-Guo Mu, Bing Shen, and Ruben Asatryan, Joanie Wisekal, Mathhew Schroeder, Ashley Hesser, Yun Liu, and Chuanming Zhou.

Equipment and facilities:
    IRMS (Finnigan MAT 253) system with TC-EA and conflo-III interface,
Laser-fluorination systems,
    Vacuum extraction lines (including GC),
    A fully equipped wet-chemistry facilities (including IC and freeze-dryer).

Specialty:
Total isotope mesurement of water-soluble oxyanions, e.g., sulfate, nitrate, and perchlorate:
d¹⁵N, d¹⁸O, d¹⁷O, d³⁴S, d³³S, and d³⁶S values for SO₄^2-, NO₃^-, or ClO₄^-

We routinely run multiple oxygen isotope composition (d18O and D17O) of sulfate extracted from diverse media (e.g. rocks, minerals, soils, riverwater, rainwater, and aerosols).

Facilities, Equipment, and other Resources

The Stable isotope laboratory suite, at LSU Department of Geology & Geophysics, consists of two rooms with a total area of ~ 1200 ft². The suite has three fume hoods, three vacuum-lines, a CO₂-laser fluorination system, a newly acquired isotope ratio mass spectrometer (IRMS) (Finnigan MAT 253). The laboratory has a research associate (M. Khachaturyan).

Wet-chemistry facilities (funded by LSU) -- These include an Ion Chromatograph system (ICS-90), one freeze-dryer, two ovens, one de-ionized water generator, two centrifuges, clean bench with worktops, binocular microscopes, an electronic top-loading balance, two ultrasonic cleaners, stir & heaters, water bath, desiccation cabinets, a corrosives cabinet, filters & apparatus, shakers, a rock crusher, and two weighing scales (down to 1 microgram). It is a fully equipped wet-chemistry laboratory supporting multiple stable isotope analyses.

A CO₂-laser fluorination system (funded by NSF and LSU) – It has been built and has analyzed > 1000 samples so far. This system (MIR 10, New-Wave Inc.) has a 30-W CO₂ laser that is computer-controlled and easy to operate. The primary purpose of this line is to fluorinate BaSO₄ to get O₂ for the measurement of both d¹⁸O and d¹⁷O values for sulfate (Bao and Thiemens, 2000). User can analyze 12 to 18 samples per working day.

Finnigan MAT 253 (Funded by NSF) – This IRMS system has 8 collectors and has been calibrated independently for Δ¹⁷O, d¹⁸O, and d¹⁵N analysis and is in excellent working condition. A TCEA system with conflo-interface III has the capacity to generate N2 and CO from AgNO₃ or CO from BaSO₄ and CsClO₄. LSU Oxy-Anion Stable Isotope Center (OASIC) is a unique stable isotope laboratory that is specialized in the isotope-ratio measurements of most elements in water-soluble oxy-anions such as sulfate, nitrate, or perchlorate. It is capable of chemical preparation and measurement of Δ¹⁷O, d¹⁸O, d¹⁷O, d¹⁵N, and multiple sulfur isotope compositions for SO₄^2-, NO₃^-, or ClO₄^-. All the stable isotope compositions can be measured to the best precisions and in the most efficient approaches thus far available in the community.

Other related facilities -- The Department of Geology and Geophysics at LSU is well equipped with analytical facilities that are supportive to this research project. It has ICP-AES (Perkin-Elmer 6500), Dionex 500 ion chromatography system, Perkin Elmer 3300 atomic absorption spectrophotometer and furnace system, JEOL 840 Scanning Electron Microscope w/ EDS x-ray probe, JEOL JXA-733 automated electron microprobe w/WDS & EDS analyzers, with cathodoluminescence detector and digital image analysis system, isotope preparation lab (Class 100 and Class 1000), X-ray powder diffractometers (Siemens and Philips), and computing facilities (e.g., SGI PowerChallenge Server and SGI Indy).

In addition, LSU have several machine shops and glass shops that serve the college and the University with very reasonable fee.

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