Stable Isotope Laboratory

Locations and Directions: 0233, 0230, and 0224 Chemistry Building 

 (301) 405 8611 (mass spectrometry laboratory)

(301) 405-1116 (chemistry laboratory)

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INSTRUMENTATION

The Stable Isotope Laboratory (Gas Source - Mass Spectrometry) CHEM 0233 is equipped with two Micromass IsoPrime mass spectrometers, one ThermoFinnigan Delta Plus mass spectrometer, and a ThermoFinnigan MAT 253 mass spectrometer. The facilities were obtained with NSF and University of Maryland funds and are overseen by two PIs (Kaufman and Farquhar). The instrumentation described below provides innumerable opportunities for cutting-edge research.

One Micromass IsoPrime is dedicated to dual inlet (DI) measurements, particularly for the automated analysis of large numbers of carbonate (C, O) and water (O, H) samples to high analytical accuracy and precision.  The system includes an automated manifold device for the extraction and sequential measurement of gas samples prepared off-line.

The other Micromass Isoprime utilizes continuous flow (CF) inlet systems coupled with high temperature combustion or reduction ovens for the automated isotopic analysis of organic matter (C, N, S, O, H), as well as mineral sulfates (S, O), sulfides (S), nitrates (N, O), and phosphates (O). Another peripheral that acts as a head space gas extractor will allow for the automated analysis of dissolved inorganic carbon (C) in water, as well as a back up device for additional carbonate and water samples typically run on the DI system.

The ThermoFinnigan Delta Plus is dedicated to simultaneous analysis of ¹⁷O/¹⁶O and ¹⁸O/¹⁶O using molecular oxygen as the analyte is presently configured for dual inlet analyses with capabilities for on-line pyrolysis of nitrate and a dedicated inlet for laser fluorination using a Synrad CO₂ laser.

The ThermoFinnigan MAT 253 is dedicated to simultaneous analysis of ³³S/³²S, ³⁴S/³²S, and ³⁶S/³²S using sulfur hexafluoride as the analyte and an on-line fluorination manifold that can be used for Ni-tube fluorinations of silver sulfide, and CO₂ laser fluorination of sulfide minerals.  We are presently developing techniques of in-situ fluorination using a Lambda Physik Compex 110 Excimer laser with KrF fill gas that is coupled to a New Wave beam delivery system and that will be coupled to a continuous flow interface.

IR and UV laser capabilities (two Synrad CO₂ lasers and one Lambda Physik Compex 110 Excimer laser) for in-situ and low blank isotopic analysis of oxygen and sulfur isotope ratios.