C60 SIMS FTICR MS raises bar for mass accuracy, resolving power

A new high-resolution mass spectrometer developed by EMSL users now allows the biological research community to identify and map the location of biomolecules on a sample with higher mass accuracy and mass resolving power than ever before. Because biological molecules with very different functions can have almost identical masses, this holistic analysis will open new doors in biological research and offer scientists unique insights into biological systems and how they work.

Called C60 SIMS FTICR MS, the new tool couples C60 (also called buckminsterfullerene, or buckyball)  secondary ion mass spectrometry, which has high spatial resolution chemical imaging capabilities and minimizes damage to biological samples during analysis, with high-magnetic field (9.4 or 12 Tesla) Fourier transform ion cyclotron resonance mass spectrometry, which has impressive mass spectral performance.

Featured on the cover of the December 15, 2011 issue of Analytical Chemistry, the team demonstrated the potential of C60 SIMS FTICR MS using mouse brain tissue. They achieved mass accuracy and mass resolving power 10 times higher than previously reported for SIMS. A solid and exciting first step for the biological research community, optimizations for the system are already underway and include achieving sub-micrometer resolution and building advanced data handling and analysis tools.

More information: Smith DF, EW Robinson, AV Tolmachev, RMA Heeren, and L Pasa-Tolic. 2011. “C60 Secondary Ion Fourier Transform Ion Cyclotron Resonance Mass Spectrometry.” Analytical Chemistry 83:9552-9556.

Provided by Environmental Molecular Sciences Laboratory (news : web)

Fresh hopes for anti-microbial potential from Aussie native plants

A research team led by QAAFI food scientist Dr. Yasmina Sultanbawa has discovered that when small amounts of the kakadu and Queensland Davidson plum are combined with organic acids they display promising new anti-microbial properties.

Dr. Sultanbawa's research team has been looking at how native plants might be used to extend the shelf-life of processed kangaroo meat in pet food, which would help to reduce the industry's reliance on preservatives such as sulphides.

“The pet food industry has traditionally used sulphites to extend the shelf-life of meat products, however extended high exposure to sulphites can lead to thiamine deficiencies in small animals including cats and dogs,” Dr. Sultanbawa said.

“Consumers are trending towards fresh, natural produce across-the-board – and that includes food choices for their beloved pets.

“The kakadu and Queensland Davidson plums both have tremendous potential as anti-microbial agents and we have only just begun to explore the protective properties of these native fruits.

“Although this is new work, our preliminary studies suggest it might be possible to improve the shelf-life of kangaroo meat by adding native plum anti-microbial agents and using existing processing such as vacuum packaging for best results.”

Department of Employment, Economic Development and Innovation (DEEDI) scientist Andrew Cusack said that this research could be applied to other minced meat products such as sausages where sulphite is used as a preservative.

“Additionally plant extracts have other benefits such as antioxidant properties which could contribute to better health,” Mr. Cusack said.

Dr. Yasmina Sultanbawa's research “Shelf-life extension of kangaroo meat using natural anti-microbials” is a collaboration between scientists from QAAFI and DEEDI's Innovative Food Solutions and Technologies.

Provided by University of Queensland (news : web)

The art of molecular carpet-weaving

Even the costliest oriental carpets have small mistakes. It is said that pious carpet-weavers deliberately include tiny mistakes in their fine carpets, because only God has the right to be immaculate. Molecular carpets, as the nanotechnology industry would like to have them are as yet in no danger of offending the gods. A team of physicists headed by Dr. Markus Lackinger from the Technische Universität München (TUM) und Professor Thomas Bein from the Ludwig-Maximilians-Universität München (LMU) has now developed a process by which they can build up high-quality polymer networks using boron acid components.

The "carpets" that the physicists are working on in their laboratory in the Deutsches Museum München consist of ordered two-dimensional structures created by self-organized boron acid molecules on a graphite surface. By eliminating water, the molecules bond together in a one-atom thick network held together solely by chemical bonds – a fact that makes this network very stable. The regular honey-comb-like arrangement of the molecules results in a nano-structured surface whose pores can be used, for instance, as stable forms for the production of metal nano-particles.

The molecular carpets also come in nearly perfect models; however, these are not very stable, unfortunately. In these models the bonds between the molecules are very weak – for instance hydrogen bridge bonds or van der Waals forces. The advantage of this variant is that faults in the regular structure are repaired during the self-organization process – bad bonds are dissolved so that proper bonds can form.

However, many applications call for molecular networks that are mechanically, thermally and/or chemically stable. Linking the molecules by means of strong chemical bonds can create such durable molecule carpets. The down side is that the unavoidable weaving mistakes can no longer be corrected due to the great bonding strength.

Markus Lackinger and his colleagues have now found a way to create a molecular carpet with stable covalent bonds without significant weaving mistakes. The method is based on a bonding reaction that creates a molecular carpet out of individual boron acid molecules. It is a condensation reaction in which water molecules are released. If bonding takes place at temperatures of a little over 100°C with only a small amount of water present, mistakes can be corrected during weaving. The result is the sought after magic carpet: molecules in a stable and well-ordered one-layer structure.

Original publication:
J F Dienstmaier, A M Gigler, A J Goetz, P Knochel, T Bein, A Lyapin, S Reichlmaier, W M Heckl, M Lackinger; "Synthesis of well-ordered COF monolayers: Surface growth of nanocrystalline precursors versus direct on-surface polycondensation"; ACS Nano Vol. 5, 12, 9737-9745.

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Metal oxide simulations could help green technology

 University of California, Davis, researchers have proposed a radical new way of thinking about the chemical reactions between water and metal oxides, the most common minerals on Earth.

Their work appears in the current issue of the journal Nature Materials.

The new paradigm could lead to a better understanding of corrosion and how toxic minerals leach from rocks and soil. It could also help in the development of "green" technology: new types of batteries, for example, or catalysts for splitting water to produce hydrogen fuel.

"This is a global change in how people should view these processes," said William Casey, UC Davis professor of chemistry and co-author of the study with James Rustad, a former geology professor at UC Davis who now works as a scientist at Corning Inc. in New York.

Previously, when studying the interactions of water with clusters of metal oxides, researchers tried to pick and study individual atoms to assess their reactivity. But "none of it really made sense," Rustad said.

Using computer simulations developed by Rustad, and comparing the resulting animations with lab experiments by Casey, the two found that the behavior of an atom on the surface of the cluster can be affected by an atom some distance away.

Instead of moving through a sequence of transitional forms, as had been assumed, metal oxides interacting with water fall into a variety of "metastable states" -- short-lived intermediates, the researchers found.

For example, in one of Rustad's animations, a water molecule approaches an oxygen atom on the surface of a cluster. The oxygen suddenly pulls away from another atom binding it into the middle of the cluster and leaps to the water molecule. Then the structure collapses back into place, ejecting a spare oxygen atom and incorporating the new one.

The U.S. Department of Energy and the National Science Foundation sponsored the research.

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The above story is reprinted from materials provided by University of California - Davis.

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Journal Reference:

James R. Rustad, William H. Casey. Metastable structures and isotope exchange reactions in polyoxometalate ions provide a molecular view of oxide dissolution. Nature Materials, 2012; DOI: 10.1038/nmat3203

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Chemical measurements confirm official estimate of Gulf oil spill rate

By combining detailed chemical measurements in the deep ocean, in the oil slick, and in the air, NOAA scientists and academic colleagues have independently estimated how fast gases and oil were leaking during the 2010 Deepwater Horizon oil spill in the Gulf of Mexico.

The new chemistry-based spill rate estimate, an average of 11,130 tons of gas and oil compounds per day, is close to the official average leak rate estimate of about 11,350 tons of gas and oil per day (equal to about 59,200 barrels of liquid oil per day).

"This study uses the available chemical data to give a better understanding of what went where, and why," said Thomas Ryerson, Ph.D., a NOAA research chemist and lead author of the study. "The surface and subsurface measurements and analysis provided by our university colleagues were key to this unprecedented approach to understanding an oil spill."

The NOAA-led team did not rely on any of the data used in the original estimates, such as video flow analysis, pipe diameter and fluid flow calculations. "We analyzed a completely separate set of chemical measurements, which independently led us to a very similar leak estimate," Ryerson said.

The new study, Chemical data quantify Deepwater Horizon hydrocarbon flow rate and environmental distribution, was published online January 9 in the journal Proceedings of the National Academy of Sciences.

The new analysis follows on another NOAA-led study published last year, in which Ryerson and colleagues estimated a lower limit to the Deepwater Horizon leak rate based on two days of airborne data collected during the spill and the chemical makeup of the reservoir gas and oil determined before the spill. The new analysis adds in many other sources of data, including subsurface and surface samples taken during six weeks of the spill and including a direct measure of the makeup of the gas and oil actually leaking into the Gulf.

Ryerson and his colleagues found that the leaking gas and oil quickly separated into three major pools: the underwater plume about 3,300-4,300 feet below the surface, the visible surface slick, and an airborne plume of evaporating chemicals. Each pool had a very different chemical composition.

The underwater plume was enhanced in gases known to dissolve readily in water, the team found. This included essentially all of the lightweight methane (natural gas) and benzene (a known carcinogen) present in the spilling reservoir fluid. The surface oil slick was dominated by the heaviest and stickiest components, which neither dissolved in seawater nor evaporated into the air. And the airborne plume of chemicals contained a wide mixture of intermediate-weight components of the spilled gas and oil.

The visible surface slick represented about 15 percent of the total leaked gas and oil; the airborne plume accounted for about another 7 percent. About 36 percent remained in a deep underwater plume, and 17 percent was recovered directly to the surface through a marine riser. The location of the balance, about 25 percent of the total, is not directly accounted for by the chemical data.

This information about the transport and fate of different components of the spilled gas and oil mixture could help resource managers and others trying to understand environmental exposure levels.

The chemical measurements made from mid-May through June showed that the composition of the atmospheric plume changed very little, suggesting little change in the makeup of the leaking gas and oil.

The team of researchers also used the detailed chemical measurements to calculate how much gas and oil, in total, was spilling from the breached reservoir deep underwater. The new chemistry-based estimate of 11,130 tons per day has an estimated range of 8,900 to 13,300 tons per day. By comparison, the official estimated range was 10,000 to 12,700 tons per day.

 

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The above story is reprinted from materials provided by National Oceanic and Atmospheric Administration.

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