Mass spectrometry of the vapours over PbBr2+MBr mixtures (M = Na, K, Rb, Cs)

1971 ◽  
Vol 24 (10) ◽  
pp. 2001 ◽  
Author(s):  
H Bloom ◽  
RG Anthony
Keyword(s):  
Mass Spectrometry ◽  
General Formula ◽  
Mass Spectrometric Study ◽  
Mass Spectrometric ◽  
Enthalpies Of Formation ◽  
Second Law ◽  
Spectrometric Study ◽  
Complex Molecules ◽  
Bipyramidal Structure

A mass spectrometric study of vapours above molten PbBr2+MBr mixtures has revealed the existence of vapour species of general formula MPbBr3 (M = Na, K, Rb, Cs). Second-law enthalpies of formation of these complexes were found to be in the range -39 to -44 kcal/mol; entropies of formation are estimated between -20 to -21 e.u. It is believed that these complex molecules have a bipyramidal structure.

scholarly journals Gas chromatographic-mass spectrometric study of metabolites of C21 and C19 steroids in neonatal porcine testicular microsomes

1985 ◽  
Vol 227 (3) ◽  
pp. 909-916 ◽  
Author(s):  
T K Kwan ◽  
N F Taylor ◽  
D Watson ◽  
D B Gower
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Mass Spectrometric Study ◽  
Mass Spectrometric ◽  
Spectrometric Study ◽  
Selected Ion Monitoring ◽  
17 Hydroxyprogesterone ◽  
Porcine Testis ◽  
Steroid Pathway ◽  
Chromatographic Mass

Microsomal fractions obtained from testes of 3-week-old piglets have been incubated, separately, with progesterone, 17-hydroxyprogesterone, 5-pregnene-3 beta,20 beta-diol, 16 alpha-hydroxypregnenolone, 5-androstene-3 beta,17 alpha-diol and dehydro-epiandrosterone. The metabolites, after derivatization, have been separated by capillary gas chromatography and identified by mass spectrometry. Quantification was by selected ion monitoring. Progesterone was shown to be 17-hydroxylated and also converted into 4,16-androstadien-3-one (androstadienone). The major metabolite of 17-hydroxyprogesterone was 4-androstene-3,17-dione (4-androstenedione), but little, if any, androstadienone was formed, indicating that this particular biosynthesis did not require 17-hydroxylation. The metabolites of 5-pregnene-3 beta, 20 beta-diol were found to be 17-hydroxypregnenolone, 3 beta-hydroxy-5,16-pregnadien-20-one (16-dehydropregnenolone) and 5,16-androstadien-3 beta-ol. Dehydroepiandrosterone and 5-androstene-3 beta,17 alpha-diol were interconvertible but neither steroid acted as a substrate for 16-androstene formation. However, dehydroepiandrosterone was metabolized to a small quantity of 4-androstenedione. Under the conditions used, no metabolites of 16 alpha-hydroxypregnenolone could be detected. The present results, together with those obtained earlier, indicate that the neonatal porcine testis has the capacity to synthesize weak androgens, mainly by the 4-en-3-oxo steroid pathway. Although 16-androstenes cannot be formed from C19 steroids, progesterone served as a substrate and may be converted directly to androstadienone, without being 17-hydroxylated first. The pathway to 5,16-androstadien-3 beta-ol, however, involves 17-hydroxypregnenolone and 16-dehydropregnenolone as intermediates.

Mass Spectrometric Study of the Gaseous Caesium Tellurides. The Enthalpies of Formation of CsTe(g), Cs2Te(g), CsTe2(g) and Cs2Te2(g)

1991 ◽  
Vol 1 (3) ◽  
pp. 86-87 ◽  
Author(s):  
Lev N. Gorokhov ◽  
Michail Yu. Ryzhov ◽  
Yuri S. Khodeev ◽  
Adolph M. Emel’yanov ◽  
Aleksei A. Nasretdinov
Keyword(s):  
Mass Spectrometric Study ◽  
Mass Spectrometric ◽  
Enthalpies Of Formation ◽  
Spectrometric Study

Compounds of aziadamantane type: Mass spectrometric study

1989 ◽  
Vol 54 (3) ◽  
pp. 691-698 ◽  
Author(s):  
Sergei D. Isaev ◽  
Nataliya F. Karpenko ◽  
Aleksandr G. Yurchenko ◽  
Luděk Vodička ◽  
Valentin I. Kadentsev ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectrometric Study ◽  
Nitrogen Molecule ◽  
Molecular Ions ◽  
Mass Spectrometric ◽  
Spectrometric Study ◽  
Molecular Ion ◽  
Mechanism Of Decomposition ◽  
Derivatives Of ◽  
Type Mass

Azi and hydrazi derivatives of adamantane,adamantanone and diamantane were studied by mass spectrometry. The EI spectra of azi derivatives lack completely molecular ions; the presence of abundant dehydroadamantane or dehydrodiamantane ions corresponds to elimination of nitrogen molecule from the molecular ion. Comparison of the EI ionization with photolysis or pyrolysis allowed to deduce some analogies and to suggest the mechanism of decomposition of the molecular ion.

Synthesis and NMR and mass spectrometric study of ammonioacetohydrazones of formylphenylboronic acids as novel ionic prospective sugar receptors

2015 ◽  
Vol 39 (6) ◽  
pp. 4695-4707 ◽  
Author(s):  
Grażyna Bartkowiak ◽  
Łukasz Popenda ◽  
Stefan Jurga ◽  
Grzegorz Schroeder
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectrometric Study ◽  
Maldi Mass Spectrometry ◽  
Mass Spectrometric ◽  
Spectrometric Study ◽  
Receptor Molecule ◽  
Ionic Group ◽  
Sugar Receptors

We report sugar receptors in which the sensitivity of detection through MALDI mass spectrometry is enhanced due to the introduction of an ionic group to the receptor molecule.

Vapour phase composition above molten salt mixtures: A mass spectrometric study

1966 ◽  
Vol 19 (6) ◽  
pp. 1003 ◽  
Author(s):  
H Bloom ◽  
JW Hastie
Keyword(s):  
Phase Composition ◽  
Alkali Metal ◽  
Mass Spectrometric Study ◽  
Vapour Phase ◽  
Divalent Metal ◽  
Mass Spectrometric ◽  
Spectrometric Study ◽  
Complex Molecules ◽  
Salt Mixtures ◽  
Salt Systems

A preliminary mass spectrometric study has been carried out on salt vapours in equilibrium with both solid and liquid CdCl2, CsCl, PbCl2, and the salt systems CdCl2 + RbCl, CdCl2+ CsCl, PbCl2 + RbCl, and PbCl2 + CsCl. The results are interpreted to indicate the existence of complex molecules of the type AMCl3 in the salt systems studied (where A is an alkali metal and M is a divalent metal).

Electrospray ionization mass spectrometric study of thallium complexes with nucleosides

2017 ◽  
Vol 23 (5) ◽  
pp. 300-304
Author(s):  
Magdalena Frańska
Keyword(s):  
Mass Spectrometry ◽  
Electrospray Ionization ◽  
Electrospray Ionization Mass Spectrometry ◽  
Mass Spectrometric Study ◽  
Mass Spectrometric ◽  
Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Spectrometric Study ◽  
Relative Affinity ◽  
Relative Abundances

The complexes between Tl+, K+, and nucleosides were studied by using electrospray ionization mass spectrometry. It was found that for complexes of 1:1 stoichiometry, thallium complexes with cytidine were the most abundant and thallium complexes with guanosine were the second most abundant ones. The relative abundances of cytidine–Tl+ to cytidine–K+ complexes depended on stoichiometry (at higher stoichiometry the potassium complexes were more abundant). In other words, the relative affinity of Tl+ and K+ to form cytidine complexes depends on the stoichiometry of the formed complexes. Guanosine–Tl+ complexes were more abundant than guanosine–K+ complexes, irrespective of stoichiometry. Both guanosine tetramer and mixed cytidine/guanosine tetramer were more abundant when they were stabilized by thallium than potassium. Therefore, Tl+ may affect the K+ stabilization of these tetramers.

Mass spectrometric study of the vaporization of the alkali chloride-cuprous chloride systems

1982 ◽  
Vol 35 (8) ◽  
pp. 1531 ◽  
Author(s):  
DJ Williams
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectrometric Study ◽  
Mass Spectrometric ◽  
Cuprous Chloride ◽  
Ion Currents ◽  
Spectrometric Study ◽  
Alkali Chloride ◽  
Enthalpy Data

Mass spectrometry has been used to determine the relative ion intensities, appearance energies and variation of ion currents with temperature, in the alkali chloride-copper(I) chloride systems. Enthalpy data for the systems have been calculated.

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