ChemWeb Newsletter

Not a subscriber? Join now.June 7, 2005

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This week, The Alchemist takes a look at a solution to farmyard smells, green solvents that are greener still, and a novel isotope of zinc. Also in this issue: nanocrystals that could revolutionize cancer diagnostics and fast and sensitive hydrogen sensors.




Argonne National Laboratory scientists have devised a new type of hydrogen sensor based on coatings commonly used on automobile windows for their water repellant properties. Physicist Zhili Xiao and colleagues demonstrated an enhanced sensor design made by depositing a discontinuous palladium thin film on a glass slide coated with a hydrophobic self-assembled monolayer of siloxane anchored to the surface. They found that the sensor shows a rapid and reversible response to hydrogen gas that is repeatable over hundreds of cycles. They say their approach to making sensors is easily scalable to an industrial level because it uses techniques that the semiconductor industry already uses. Hydrogen sensors will form an essential component of a future hydrogen economy.





Hydrogen peroxide is usually the preserve of those who prefer their hair a lighter shade, but now US chemists have discovered that mixed with horseradish, it can rid farms of the foul stench of pig waste. The suffocating stench of hog farms can overwhelm people living close by and as farms get bigger and more people move to the country, the problem can only get worse. Jerzy Dec and his colleagues at Pennsylvania State University report in a forthcoming issue of J Agric Food Chem how they have made a simple mixture that can dampen the smell. The malodorous chemicals giving rise to the stench are generally phenols. Peroxide acts as an activator for the peroxidases in the pungent horseradish root, which then oxidize these phenols, neutralizing the odor. Potatoes, white radish roots, and soybean hulls are alternative sources of peroxidases and could be used to neutralize other manure smells.





Cheap and clean alternatives to volatile organic solvents (VOCs) are at last proving their credentials. Room temperature ionic liquids (RTILs) are attracting keen interest in academic research laboratories but have until now struggled to enter the industrial mainstream. Recently, two major chemical companies, the Eastman Chemical Company and BASF, have developed processes that use ionic liquids. Researchers are now focusing their efforts on how to ensure that ionic liquids really are safe for the environment and human health. Researchers at Monash University in Melbourne, Australia, have for instance developed an ionic liquid that is biodegradable. "Ionic liquids are not intrinsically green; we have to design them to be green," explains Ken Seddon, who runs the Queen's University Ionic Liquid Laboratories in Belfast, UK. The Monash discovery could do just that.





An international team of researchers has produced a new isotope of zinc, zinc-54, which they say undergoes the rare process of two-proton decay. The research carried out by Bertram Blank of the CENBG laboratory in France and colleagues could shed light on what how protons stay together in the atomic nucleus. Carrying out nuclear physics experiments with this new isotope is relatively straightforward but don't expect to see it bottled for off-the-shelf chemistry. The manufacturing process is very low yield with only one in 10 to the 17 collisions between nickel-58 atoms and a nickel target yielding the novel zinc-54 species.





An interdisciplinary collaboration between researchers from France, Russia, and Britain has led to a method of labeling specific molecules within cells using nanoscale marker particles. The nanoparticles can be detected from their very strong fluorescence when any light from ultraviolet to red is shone on them. The team is already testing in real-time samples taken from cancer patients and finding they can spot tell-tale markers associated with the disease. Existing fluorescent dyes suffer from photodegradation but these crystalline nanoparticles extremely stable and fluoresce for many days.