摘要:

Complex-formation between carbohydrates and cations may have important biological implications. Potassium ions and sucrose interactions have been observed by the examination of the spectral patterns obtained by multi-dimensionnal analysis (Principal Component Analysis) applied to infrared spectra of biological samples. Several authors have extensively studied ions-sugars interactions particularly calcium and magnesium-sugar interactions and have shown that these interactions induced shifts and splitting in infrared absorption bands.

ISSN:0038-7010    

DOI:10.1080/00387019708002585

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Fourier transform infrared spectroscopy has been used to study quantitatively the acetylation of monodisperse polystyrene microspheres diametres ranging from 7 to 9μ. The CH2stretching infrared vibration mode at 2921 cm−1was used as the internal intensity standard. The acetylation extent could be easily measured by comparing the relative intensities of the bands of acetyl group (1678; 1415, 1359 cm−1) or the bands due to the para-substituted benzene ring to the band at 2921 cm−1from the calibration curve.

ISSN:0038-7010    

DOI:10.1080/00387019708002586

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The aim of this work was to investigate a simple and reliable method for the determination of trace amounts of famotidine, fluconazoie and ketoconazole in bulk powder and in their pharmaceutical dosage forms. Also to study the different factors affecting the sensitivity of the synchronous technique in order to improve the measurement The sample was prepared in methanol in case of famotidine and ketoconazole, and in water, after dissolution in methanol, in case of fluconazoie. The fluorescence intensity was recorded at 384 (ex. at 284 nm), 285 (ex. at 255 nm) and 364 nm(ex. at 239 nm) for famotidine, fluconazole and ketoconazole respectively. The calibration curves were linear over the concentration ranges 15 50, 0. 20–10 and 0. 02–0. 4 μg/ml for famotidine, fluconazole and ketoconazole respectively.

ISSN:0038-7010    

DOI:10.1080/00387019708002587

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

A low-temperature high-resolution luminescence study of Ag2Eu(DTPA) H2O has been carried out. The Eu3+luminescence spectrum was recorded over the spectral range which includes transitions from the5D0excited state to the7F0-6ground state manifolds and from the5D1excited state to the7F0-2ground state manifolds. The observed spectral patterns are analyzed using group theoretical methods so as to deduce the site symmetry of the Eu3+ion in the complex. The analysis shows that the Eu3+ion occupies a spectroscopic site symmetry that approaches a C2vsymmetry with distortion towards C2or lower symmetry. Results from the analysis are compared with previously reported Xray crystallographic results. In addition, the transition energies exhibited in the emission spectrum have been used to calculate the relative energies of the electronic levels characteristic of Eu3+ions in the title compound.

ISSN:0038-7010    

DOI:10.1080/00387019708002588

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The crystalline lanthanide complexes (except Ce and Pm) with proline were synthesized. The general formula of [Ln(Pro)2(H2O)4]3(ClO4)3of the complexes were obtained from chemical analysis, elemental analysis, TG-DTA analysis and electrical conductivity. Infrared spectra reveal a considerable shift of the symmetric co2stretching mode from lower to higher energies in the lanthanide complexes and a decrease of Δv(Δv=vcoo-as-vcoo-s) from 212 cm−1in proline to about 167 cm−1in the complexes. The peak mean 405cm−1in the Raman spectra varies with the total orbital angular smomentum of the lanthanide ions in the ground states, exhibiting a profile of an “inclined w”. These spectral features in the IR and Raman spectra were regarded as strong evidences of Ln-O bonding. The peak near 405cm1was assigned as the Ln-O stretch modes.

ISSN:0038-7010    

DOI:10.1080/00387019708002589

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Using the product operator technique, an analytical description of heteronuclear 2D-J resolved NMR spectroscopy for a weakly coupledISn(I=I/2,S=1, n=1, 2, 3) spin system is presented. As a pulse sequence, the most commonly used one, the gated decouple sequence, is used. The obtained analytical results were found to be in good agreement with the experimental ones.

ISSN:0038-7010    

DOI:10.1080/00387019708002590

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The infrared spectra of three compounds of the MIMIIIS2type (smithite, AgAsS2; weissbergite, TlSbS2; and miargyrite, AgSbS2) were studied at room temperature (RT) and at the boiling temperature of liquid nitrogen (LNT). The infrared spectrum of smithite was compared with that of the formally analogous mineral lorandite, TlAsS2. Although the mentioned synthetic minerals have crystal structures, which differ from each other, the infrared spectra of smithite and lorandite, on the one hand, and of weissbergite and miargyrite on the other, are similar. The analysis of the spectra indicate that the Tl-S interaction has a more pronounced ionic character than the Ag-S one.

ISSN:0038-7010    

DOI:10.1080/00387019708002591

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The mechanochemical transformations of Ag, Hg and Pb cyano complexes (ferro-and ferricyanides, cobalticyanides, nitroprussides, hexacyanoplatinates and tetracyanonickellates) during milling and pressing with KBr have been studied using IR, XRD and Mossbauer techniques as sensors. Exchange of K+and the heavy metal cations is observed in all cases.

ISSN:0038-7010    

DOI:10.1080/00387019708002592

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Fourier transform infrared classical computation method applied to the direct quantitative analysis of multicomponent gaseous mixtures of the organic compounds was described in the paper. For the analysis of multicomponent mixtures a number of important problems, such as select of quantitative optimal peak windows and calibration of the spectral band overlapping between the compounds, had been discussed. The FT-IR software for multicomponent simultaneous determination of up to 10 compounds in a gaseous mixture had been completed. The software can provide two kinds of the linear and nonlinear fits for the calibrating concentrations of the interference components. The accuracy, precision and time of the analysis were satisfactory. The results indicate that the method can be used for the simultaneous quantitative analysis of the multicomponent gaseous mixtures of the organic compounds even if there are serious overlaps of the infrared spectral absorption bands of the compounds.

ISSN:0038-7010    

DOI:10.1080/00387019708002593

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Infrared spectra of free and bound with different proton acceptors in 1:1 and 1:2 complexes H-bonded molecules of 3, 5-dichloroaniline, 3, 5-dibromoaniline, 2, 3, 5, 6-tetrafluoroaniline, 4-methoxytetrafluoroaniline, pen-tafluoroaniline, 4-nitro-anihne, 2, 6-dichloro-4-nitroaniline, 4-nitrotetraflu-oroaniline and 4-aminotetrafluoropyridine were studied in the region of stretching and deformational vibrations of amino group. Spectral characteristics of absorption bands of free and bound H-bonded molecules of substituted anilines in solutions were determined.

ISSN:0038-7010    

DOI:10.1080/00387019708002594

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor