摘要:

A reliable and sensitive analytical optical method for the determination of phosphorous in oceanographic and environmental materials does not exist. In this work, a novel hydride generation method was used to form phosphine from a sample containing phosphate mixed with 7% sodium borohydride. By heating the mixture to 500 °C, phosphine was reproducibly generated and collected in a cold trap. Phosphine was then introduced into an ICP where several atomic emission lines for phosphorous were observed. Copper emission did not spectrally interfere with phosphorous atomic emission with this hydride generation-ICP-AES method. This hydride generation method allows the use of small sample volumes (< 5 μL).

ISSN:0038-7010    

DOI:10.1080/00387018908054010

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The previously unassigned carbon-13 NMR resonances of the side-chain carbon atoms of the enzyme inhibitor dipropylglyoxal bis(amidinohydrazone) (DPGBG) have been unambiguously assigned with the aid of DEPT measurements and experiments involving the selective decoupling of the protons of one of the methylene groups. The chemical shifts of the side-chain carbon atoms of DPGBG decrease in a nearly linear fashion as a function of the position of the atom in the side chain, the terminal methyl groups having the lowest shift value. The carbon-13 shifts are positively correlated with the chemical shifts of the corresponding hydrogen atoms.

ISSN:0038-7010    

DOI:10.1080/00387018908054011

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Molecular mechanics calculations were made for 1,1-dichlorobutane, 2,2-dichlorobutane, and 1,2-dichloro-2-methylpropane in order to compare the results with conclusions obtained from vibrational spectra concerning the conformational behavior of these compounds. Calculations were also made for 1,2-dichloro-2-methylbutane, although vibrational spectra are not available for this compound. The structures and relative energies of the most abundant conformers are given.

ISSN:0038-7010    

DOI:10.1080/00387018908054012

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The1H-nmr and infrared spectra of the complexes [M(ox)n(Hox)] where M = UO2(n = 2), Th (n = 4) or Sc (n = 3) and Hox = 8-hydroxyquinoline are discussed. The nmr spectra of the adducts are uninformative with respect to the bonding and structure of these molecules since they dissociate in solution. The solid state ir spectra show that the adducted molecule of 8-hydroxyquinoline is bound to the metal through the phenolic oxygen, the proton forming an intramolecular hydrogen bond between the nitrogen atom of the adducted molecule and the oxygen atom of a neighbouring chelate ring. The mid-and far-ir spectra are reported for the first time and assignments for the δN-H, νM-O and νM-N modes have been made.

ISSN:0038-7010    

DOI:10.1080/00387018908054013

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A spectroscopic method is described for the determination of Metformin based on its formation of molecular complex with iodine in dichloroethane. Quantitative measurements are made at the maximum absorption of 295nm. The molar ratio of the formed metformin-iodine complex is 1:1 as revealed by Job's method. Beers' law is obeyed in the range 2–12 ug.ml−1base solution. The proposed method is statistically comparable with the official B. P. method. When applied to pharmaceutical preparation, tablets, average percentage recovery of 99.97 ± 0.81 was obtained.

ISSN:0038-7010    

DOI:10.1080/00387018908054014

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A study is carried out by FT-IR spectroscopy of the carbonate species formed upon interaction of CO2with alumina and vanadia-alumina catalysts doped with sodium. It is found that the presence of sodium enhances the ability of the catalyst surface to adsorb CO2, yielding to carbonate formation. The species formed changes in the presence of vanadium, shifting the νCOOstretching bands towards higher wavenumbers than those recorded in Na-Al2O3systems.

ISSN:0038-7010    

DOI:10.1080/00387018908054015

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The influence of solvents on the electronic absorption spectra of chromium (III) complexes was investigated. The dependence of the crystal field parameter Dq on dielectric constant as well as Gutmann donor number DN of solvent was found and described. By using the proposed model, unknown in the literature donor numbers for a few alcohols were estimated.

ISSN:0038-7010    

DOI:10.1080/00387018908054016

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A method for simultaneous spectrophotometric determination of total iron, iron(II) and iron(III) in mixtures containing other metal ions has been described. The method is based on the complexation of iron with di-2-pyridyl ketone benzoylhydrazone (DPKBH) in 50% (v/v) ethanolic solution. Iron(II) complex with DPKBH exhibits two absorption maxima at 360 and 650 nm. meanwhile iron(II1) complex with DPKBH exhibits only one maximum at 360nm. Iron(II) and iron(III) complexes with DPKBH have similar behaviour at 360nm. Iron forms 1:2 complexes with the reagent. Beer's laws are obeyed over the ranges 0.1–2 μgml-1 and 0.4–5 μgrn1-l for iron(II) complexes at 360 and 650nm respectively. Iron(III) showed results similar to those obtained for iron(II) at 360nm. The effect of pH, effect of excess reagent. the stability of complexes. and the tolerance limit of many metal ions have been reported. The method is applied to the determination of total iron, iron(I1). and iron(II1) in synthetic solutions.

ISSN:0038-7010    

DOI:10.1080/00387018908054017

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Vibrational spectra of 2-benzoyl pyridine and 2-benzoyl pyridine-18O have been recorded in the solid and molten state in the infrared (4000–100 cm−1) and in the Raman (4000–50 cm−1). Polarized Raman spectra in the molten state have also been measured. The assignment of the vibrational bands is performed using the group vibrational concept, isotopic shifts and polarization features of the normal modes.

ISSN:0038-7010    

DOI:10.1080/00387018908054018

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Absorption spectra of benzene cation radical, chlorobenzene cation radical, and fluorobenzene cation radical have been obtained in perfluorocarbon polymer at 77 K. Cation radicals are formed in good yields and less perturbed electronic absorption spectra are obtained. Results demonstrate that perfluorocarbon polymer is suitable as matrix for spectroscopic investigation of the cation radicals formed by γ-irradiation.

ISSN:0038-7010    

DOI:10.1080/00387018908054019

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor