نتایج جستجو برای: trimethylsilylation
تعداد نتایج: 65 فیلتر نتایج به سال:
Trimethylsilylation of chitin was studied in detail to establish a reliable method, and the properties of the resulting product were elucidated. Chitin was successfully trimethylsilylated with a mixture of hexamethyldisilazane and trimethylsilyl chloride in pyridine. Compared to alpha-chitin, beta-chitin was much more reactive and advantageous as a starting material to prepare fully substituted...
Novel thin and smooth deuterated cellulose films were synthesised to visualize adsorbed bio-macromolecules using contrast variation neutron reflectivity (NR) measurements. Incorporation of varying degrees of deuteration into cellulose was achieved by growing Gluconacetobacter xylinus in deuterated glycerol as carbon source dissolved in growth media containing D2O. The derivative of deuterated c...
"Hydrophobic chromatography", which is a variation of reverse phase chromatography, is applicable to the analysis of cephalosporin C derivatives, especially in fermentation broths. Unfortunately, there are no commercial C18 columns which are entirely suitable for this class of compounds. For this reason C18 columns were prepared by an in-situ bonding technique and were optimally designed for ce...
Kraft lignin, so far useful for energy generation, has been gathering considerable attention as an alternative material to replace fossil-based resources mainly due its high phenolic content. However, the wide molecular weight distribution and chemical composition heterogeneity led development of fractionation methods. Herein, narrow such characteristics we used eucalypt kraft lignin fractionat...
Parallel to the "poppy-seed defense" strategy commonly reported in the United States, donors of urine samples tested positive for opiates in Taiwan often claimed the consumption of Brown Mixture (BM) as the source of the observed morphine and codeine. Because BM contains opium powder (10.0-10.5% morphine), opium tincture (0.9-1.1% morphine), or camphorated opium tincture (0.045-0.055% morphine)...
Enzymatic digestion with beta-glucuronidase (EC 3.2.1.31) was used to release intact oxazepam from urine samples containing the d5-analog internal standard. The resulting specimens were extracted with Du Pont PREP Type W cartridge (processed by a PREP Automated Sample Processor), Bond Elut Certify, and J.T. Baker "spe" columns for comparison of the columns' extraction recovery and overall effec...
Microstructural and mechanical properties of organic surfactant templated nanoporous thin silica films have been studied by X-ray diffraction, Fourier transform infrared spectroscopy, and nanoindentation. Compared with many other porous low-k dielectrics, the self-assembled molecularly templated nanoporous silica films demonstrate better mechanical properties. This is ascribed to the presence o...
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