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Development of a micro flow-through cell for high field NMR spectroscopy

Alam, Todd M.; McIntyre, Sarah K.

A highly transportable micro flow-through detection cell for nuclear magnetic resonance (NMR) spectroscopy has been designed, fabricated and tested. This flow-through cell allows for the direct coupling between liquid chromatography (LC) and gel permeation chromatography (GPC) resulting in the possibility of hyphenated LC-NMR and GPC-NMR. The advantage of the present flow cell design is that it is independent and unconnected to the detection probe electronics, is compatible with existing commercial high resolution NMR probes, and as such can be easily implemented at any NMR facility. Two different volumes were fabricated corresponding to between {approx}3.8 and 10 {micro}L detection volume. Examples of the performance of the cell on different NMR instruments, and using different NMR detection probes were demonstrated.

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TYPE SAND Report YEAR 2011
OSTIDOI

Metabonomics for detection of nuclear materials processing

Alam, Todd M.; Alam, Mary K.

Tracking nuclear materials production and processing, particularly covert operations, is a key national security concern, given that nuclear materials processing can be a signature of nuclear weapons activities by US adversaries. Covert trafficking can also result in homeland security threats, most notably allowing terrorists to assemble devices such as dirty bombs. Existing methods depend on isotope analysis and do not necessarily detect chronic low-level exposure. In this project, indigenous organisms such as plants, small mammals, and bacteria are utilized as living sensors for the presence of chemicals used in nuclear materials processing. Such 'metabolic fingerprinting' (or 'metabonomics') employs nuclear magnetic resonance (NMR) spectroscopy to assess alterations in organismal metabolism provoked by the environmental presence of nuclear materials processing, for example the tributyl phosphate employed in the processing of spent reactor fuel rods to extract and purify uranium and plutonium for weaponization.

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TYPE Conference YEAR 2010
OSTI

Tracking of Nuclear Production using Indigenous Species: Final LDRD Report

Alam, Todd M.; Alam, Mary K.

Our LDRD research project sought to develop an analytical method for detection of chemicals used in nuclear materials processing. Our approach is distinctly different than current research involving hardware-based sensors. By utilizing the response of indigenous species of plants and/or animals surrounding (or within) a nuclear processing facility, we propose tracking 'suspicious molecules' relevant to nuclear materials processing. As proof of concept, we have examined TBP, tributylphosphate, used in uranium enrichment as well as plutonium extraction from spent nuclear fuels. We will compare TBP to the TPP (triphenylphosphate) analog to determine the uniqueness of the metabonomic response. We show that there is a unique metabonomic response within our animal model to TBP. The TBP signature can further be delineated from that of TPP. We have also developed unique methods of instrumental transfer for metabonomic data sets.

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TYPE SAND Report YEAR 2009
OSTIDOI

Exploiting interfacial water properties for desalination and purification applications

Cygan, Randall T.; Jiang, Ying B.; Alam, Todd M.; Brinker, C.J.; Bunker, B.C.; Leung, Kevin L.; Nenoff, T.M.; Nyman, M.; Ockwig, Nathan O.; Orendorff, Christopher O.; Rempe, Susan R.; Singh, Seema S.; Criscenti, Louise C.; Stevens, Mark J.; Thurmer, Konrad T.; Van Swol, Frank; Varma, Sameer V.; Crozier, Paul C.; Feibelman, Peter J.; Houston, Jack E.; Huber, Dale L.

A molecular-scale interpretation of interfacial processes is often downplayed in the analysis of traditional water treatment methods. However, such an approach is critical for the development of enhanced performance in traditional desalination and water treatments. Water confined between surfaces, within channels, or in pores is ubiquitous in technology and nature. Its physical and chemical properties in such environments are unpredictably different from bulk water. As a result, advances in water desalination and purification methods may be accomplished through an improved analysis of water behavior in these challenging environments using state-of-the-art microscopy, spectroscopy, experimental, and computational methods.

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TYPE SAND Report YEAR 2008
OSTIDOI

Cupric siliconiobate. Synthesis and solid-state studies of a pseudosandwich-type heteropolyanion

Inorganic Chemistry

Anderson, Travis M.; Alam, Todd M.; Rodriguez, Marko A.; Bixler, Joel N.; Xu, Wenqian; Parise, John B.; Nyman, M.

The Na+ and [Cu(en)2(H2O) 2]2+ (en = ethylenediamine) salt of a pseudosandwich-type heteropolyniobate forms upon prolonged heating of Cu(NO3)2 and hydrated Na14[(SiOH)2Si2Nb 16O54] in a mixed water-en solution. The structure [a = 14.992(2) Å, b = 25.426(4) Å, c = 30.046(4) Å, orthorhombic, Pnn2, R1 = 6.04%, based on 25869 unique reflections] consists of two [Na(SiOH)2Si2Nb16O54]13- units linked by six sodium cations, and this sandwich is charge-balanced by five [Cu(en)2(H2O)2]2+ complexes, seven protons, and three additional sodium atoms (all per a sandwich-type cluster). Diffuse-reflectance UV-vis indicates that there is a λmax at 383 nm for the CuII d-d transition and the 29Si MAS NMR spectrum has two peaks at -78.2 ppm (151 Hz) and -75.5 ppm (257 Hz) for the two pairs of symmetry-equivalent internal [SiO4]4- and external [SiO3(OH)]3- tetrahedra, respectively. Unlike tungsten-based sandwich-type complexes, the [Na(SiOH)2Si 2Nb16O54]13- units are linked exclusively by Na+ instead of one or more d-electron metals. © 2008 American Chemical Society.

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TYPE Journal Article YEAR 2008
ScopusOSTIDOI
Results 151–175 of 231
Results 151–175 of 231