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Characterization of micelles and liposomes using the Eclipse 3+ AF4 separation system coupled to a DAWN HELEOS II MALS detector
Micelles and liposomes can serve as vehicles used to solubilize and carry bioactive compounds to their site of action, thus increasing their bioavailability. First experience has been made using vitamins and enzymes as functional food additives. Moreover, micelles could be useful to deliver drugs to a defined site of action, thus reducing frequently occurring side effects of systemic drug administration. Micelles are true nano-materials with a size range of 10 to 30 nm in diameter. Ideally, they should have a narrow size distribution. Furthermore, they have to be stable and should release their active compound only in the target region. Characterization of the micelle suspensions is vital to guarantee these properties and has to cover several aspects. One important point is size distribution, which has to be determined with high resolution...
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Improvement of power generation efficiency of solar cells and evaluation by fluorescence spectroscopy
The light in the high-radiance wavelength region of the solar spectrum is not utilized effectively by silicon crystal-based solar cell modules. "Fluorescent materials" convert the ultraviolet component in the sunlight into light in the longer wavelength region where this solar cell modules can generate power. This article describes an example, how the efficiency of a fluorescent material can be evaluated, using a fluorescence spectrophotometer equipped with an integrating sphere, and a special program, which allows the determination of quantum yields of powders in a very comfortable way....
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Detection of NADH and NADPH with the Omega's High Speed, Full UV/Vis Absorbance Spectrometer
Nicotinamide Adenine Dinucleotide (NAD+), reduced nicotinamide adenine dinucleotide (NADH), nicotinamide adenine dinucleotide phosphate (NADP+) and reduced nicotinamide adenine dinucleotide phosphate (NADPH) have been known to play vital roles in energy metabolism, antioxidation, and reductive biosynthesis. In recent years, these co-factors have been shown to be involved in other physiological functions as well, including aging, oxidative stress, intracellular calcium homeostasis, ROS production, cell death and gene expression....
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UV/Vis/NIR Spectrometry for the Film Thickness Determination of Transparent Films and Layers
Within nearly all branches of industry we find products, which are coated with thin transparent layers to improve the surface features: Window sheet glasses obtain changes in reflection and absorption behavior, ceramics are treated with coatings to lower water adhesion, coatings on metals create corrosion resistance or better sliding factors. Transparent coatings play also a major role in the semiconductor business. One of the important features to be determined and controlled is the thickness of the layers to balance performance and material input during development and production...
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The Determination of Hazardous Substances According to RoHS and WEEE Directives
1st July 2006 is an important deadline for the electro- and electronics industries. This date bans hazardous substances like lead, cadmium, mercury, hexavalent chromium and polybrominated biphenyls and diphenyl ethers from electro- and electronic equipment. This restriction, even though in discussion since 1991, has become more and more important from year to year because of tons of electronic waste releasing toxic substances which are accumulated in the environment, the food chain and all human beings. In order to enforce the substances ban and the limitation or substitution of hazardous components, elemental analysis is obviously the most important control measure for monitoring limiting values. This requires precise analytical systems such as X-ray fluorescence, ICP- and atomic absorption spectrometers. These instruments are able to detect trace concentrations of hazardous compounds - for example cadmium, using an atomic absorption spectrometer in the flame atomization mode up to 0.1 mg/L, or using the di...
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