Application Notes: General
IC–ICP–MS Speciation Analysis of As in Apple Juice
February 1st 2012In this study, apple juice samples are analyzed by IC–ICP–MS to determine the concentration of six arsenic species: the two inorganic, and highly toxic, species (As (V) and As [III]) and four organic species (arsenobetaine [AsB], arsenocholine [AsC], monomethylarsonic acid [MMA], and dimethylarsinic acid [DMA]).
Microwave Digestion of Pharmaceutical Finished Products and Ingredients for Upcoming USP Method 233
February 1st 2012Current USP Method 231 "Heavy Metals" was introduced in 1905 for determining heavy metal impurities in pharmaceutical drug products. The procedures of the method have several limitations, which produce results that are nondiscriminatory, difficult to reproduce, and qualitative, or at best, semi-quantitative.
Fast Quality Evaluation of Bulk Polymers and Products Using FT-NIR Spectroscopy
September 1st 2011FT-NIR spectroscopy for the quantitative determination of key physical parameters in bulk polymers and products, including density and melt index (MI). These measurements can often be made with little or no sample preparation.
Comparison of Secondary Structures of Similar Proteins Using Automated CD
September 1st 2011In this study, far-UV CD spectra of eight different mammalian serum albumins were measured repeatedly using automated CD spectroscopy. Two independent methods of normalizing the CD data were used to eliminate the need for accurate knowledge of protein concentration or extinction coefficient. The normalized far-UV data, representative of secondary structure, were compared to determine if there were statistically significant differences between samples. The two normalization methods agreed in every case, increasing confidence in the results.
Sample Preparation for NIR Analysis
September 1st 2011A much discussed issue related to near infrared analysis (NIR) is the necessity of sample preparation. Ground and unground samples of wheat were analyzed to determine how truly necessary it is to homogenize samples before NIR analysis. The new Retsch TWISTER mill, specifically designed for NIR sample preparation, was utilized for this comparative study.
Raman Analysis of Si Crystallinity
September 1st 2011While crystalline silicon (c-Si) is still the material of choice for modern solar cell manufacturing, the drive toward lower cost, more efficient solar cells is prompting a renewed interest in thin-film amorphous silicon (a-Si). In light of this, it is more important than ever to have the ability to quickly identify Si crystallinity, both qualitatively and quantitatively. In this application note, we evaluate how a portable Raman spectrometer can be used in conjunction with a portable video microscope to measure crystallinity.
Enhanced Sensitivity to Detect Phthalates by FT-IR Analysis
September 1st 2011Recent evidence that the phthalate plasticizers may cause health problems, particularly in children, has resulted in many countries prohibiting the use of phthalates in toys and clothing. The United States Child Safety Law actually prohibits the presence of several phthalate compounds at levels exceeding 0.1 wt % even though the commercial levels are often greater than 10%. While ATR spectroscopy works well for identifying phthalates at commercial levels, a more sensitive technique is required to detect trace levels.
UV-Vis-NIR Spectrophotometer Analyzer Comparison
September 1st 2011The Moxtek Proflux UVC266 analyzer improves UV–vis NIR spectrophotometer performance. As the analyzer polarizer, the UVC266 conserves space, offers an exceptionally wide cone acceptance angle, and has no disturbance issues as does the Glan-Taylor prism due to its air-gap.
Disinfection of Tetraselmis sp. with UV LED Application
Analyzing the effect of UV LED modules on disinfecting ballast water using UV–vis spectroscopy.
NIR Micro-Photoluminescence Characterisation of Single Semiconductor Quantum Wires
September 1st 2011Nanoscale structures (quantum dots and quantum wires) are being studied extensively with a view to building ever more exotic devices, such as more efficient lasers and LEDs, or quantum information processing components. One type of material under investigation consists of semiconductor quantum wires based on InAs.
Temperature Induced Changes in Clays Measured by Diamond ATR FT-IR Spectroscopy
September 1st 2011Increasing temperature can cause chemical changes, alter reaction rates, concentrate an aqueous sample, or evaporate a solvent. These transformations can be readily monitored by diamond ATR spectroscopy. This note explores the use of a diamond ATR to examine heat-induced changes in the clay.
Topographic Confocal Raman Imaging using True Surface Microscopy
September 1st 2011True surface microscopy for topographic confocal Raman imaging adds optical profilometer functionality to a highly sensitive confocal Raman microscope. Using this profilometer function, topographic scans of several square millimeters can be acquired, similar to a very large AFM topography image. This acquired large-area topography image can be used to trace the surface contours while acquiring a confocal Raman image.
The Orbis Micro-XRF Analyzer Series
September 1st 2011Building on more than 10 years of Micro-XRF experience, the Orbis spectrometer yields a system with excellent Micro-XRF capability while setting a new standard in analytical flexibility. The Orbis incorporates a unique motorized turret integrating video and X-ray optics allowing coaxial sample view and X-ray analysis. The turret can accommodate two additional collimators along with the X-ray optic for a total of three X-ray beam sizes to expand the Orbis analytical capabilities beyond traditional Micro-XRF analysis. Primary beam filters can be used with all spot sizes available on the turret to allow true XRF analytical capabilities in a micro-spot analysis. The working distance is increased to allow analysis over rougher sample topography without sacrificing signal intensity.