نتایج جستجو برای: uv spectra
تعداد نتایج: 172424 فیلتر نتایج به سال:
Copper (II) phthalocyanine and 2, 9, 16, 23 tetrakis nitro copper (II) phthalocyanine has been synthesized respectively from phthalonitrile and 4-nitro phthalonitrile under solvent-free condition using two different catalysts over nanodimensional zeolites. 4-Nitro phthalonitrile synthesized from phthaimide in three steps. The newly prepared compounds have been characterized by IR, UV-Vis,1H N...
A method is developed for the analysis of allantoin, gallic acid, dihydromelittoside, loganin, paeoniflorin, benzoylpaeoniflorin, and paeonol in Liuwei Dihuang tablets by high-performance liquid chromatography (HPLC)-UV-mass spectrometry (MS)-MS. Gradient elution with methanol-acetonitrile-water-formic acid solvent system is employed in the HPLC-electrospray ionization-MS study. The positive-io...
UV irradiation of 1,3-dimethyluracil in ice-matrix yields four dimeric dimethyluracils (2 c) — (5 c) , which could be isolated by preparative thin-layer chromatography. Attemps for structure elucidation of these four dimers by UV, IR, NMR and mass-spectrometric methodes pointed out, that only NMR-spectra give structural evidences; by IR — not by mass-spectra — certain identification of dimers i...
We demonstrate the application of linear arrays of ultraviolet light emitting diodes (UV LEDs) at the wavelengths of 280 nm and 340 nm to the acquisition of fluorescence spectra from single particles in realtime. A compact optical system and custom electronics are employed to produce a compact, standalone biosensor. The detection sensitivity of the UV LED system is established using the biofluo...
This Application Note describes the development of reliable quality control methods for analysis of individual traditional Chinese medicines (TCMs) and TCM formulations using rapid resolution liquid chromatography with UV-visible and quadrupole mass spectrometry detection. The chromatograms obtained with UV and MS detection for different individual TCMs are compared and the combination of UV an...
Chemometric methods like Principal Component Analysis (PCA) and Evolving Factor Analysis (EFA) have been applied to improve peaks separation, especially in HPLC UV-DAD analysis. In this work, the Independent Component Analysis (ICA) was adopted for the separation of overlapping aromatic peaks and the simultaneous determination of the underlying spectra. The application of the method on middle p...
The KGd2F7:Tb and KGd2F7:Tb,Eu samples were obtained using a solid state reaction. Excitation spectra and emission spectra are reported and analyzed within the VUV–UV–vis spectral range. The intense green luminescence is observed in the KGd2F7:Tb while the combined emission of terbium and europium in the KGd2F7:Tb,Eu covers substantially the region of white light. The materials under study can ...
In this article, the optimized geometry, IR and UV spectra, frontier orbital analysis, natural bond orbital (NBO) analyses, and thermodynamic parameters of pomalidomide were investigated. The calculated structural parameters and stretching frequencies values are compared with experimentalvalues of the investigated compound. Also, the relations of the thermodynamic functions vs.temperatures were...
ZnO nanorods (NRs) were synthesized using an in situ low-temperature hydrothermal method. In order to investigate the effect of different seed layers on quality of ZnO NRs arrays, alcoholic, alkaline and acidic seed solutions were deposited by spin coating on ITO-glass substrate. Experimental results revealed that the vertically ZnO NRs obtained from monoethanolamine-based seed layer is the...
A novel zinc oxide - agar nanocomposite was successfully synthesized using zinc chloride as a precursor. The nanocomposite was prepared using a domestic microwave oven. The prepared nanocomposites have been characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and UV- visible spectroscopy. The crystalline properties...
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