J. D. Wander

Quantitative, multicomponent analysis of fatty acids from cholesteryl esters by chemical ionization reconstructed mass chromatography

Reconstructed mass chromatography using methane as a carrier and reagent gas for chemical ionization gas chromatography-mass spectrometry of the derived methyl esters allows rapid, quantitative microdeterminations of complete cholesteryl ester fatty acid profiles. The sensitivity of this method is consistent with completely specific, multicomponent assay at the picomole level. Introduction of two homologues as internal standards, one into the intact biological specimen and the other after derivatization, provides a measure of the net efficiency of the processes of extraction and derivatization. This procedure may be extended readily to the determination of fatty acid profiles in most biological fluids.

Antioxidants in neoplastic cells: II. Isolation and partial characterization of a phenolic antioxidant from differentiated mouse neuroblastoma cells.

The generation of an antioxidant has been shown to be associated with the dramatic increase in resistance to lipid peroxidation which occurs during the differentiation of mouse neuroblastoma cells in culture. The antioxidant has been isolated from the neuroblastoma neutral lipid fraction and partially characterized by means of low-resolution and high-resolution mass spectrometry and other lines of evidence. All presently available information suggests that this antioxidant is a highly aromatic, monosubstituted phenol having the molecular formula C19H14O2.

Isosucrose. Definitive structural assignment by spectral correlation to α,β- and α,α-sucrose octaacetates

Abstract Three nonreducing disaccharides containing D -glucosyl and D -fructosyl groups, namely, “isosucrose” octaacetate ( 3 ), sucrose octaacetate ( 4 ), and “α,α-sucrose” octaacetate ( 5 ), give qualitatively identical mass spectra and are, therefore, related as diastereoisomers. Spin-coupling values in the 300-MHz n.m.r. spectra of 3 , 4 , and 5 establish that the D -glucopyranosyl group is present in the 4 C 1 ( D ) conformation, and that the anomeric configuration of this group is α in 4 and 5 , and β in 3 . In the n.m.r. spectra, the H-4 atom of the D -fructofuranosyl group of 3 and 5 resonates 0.5 p.p.m. upfield of the corresponding signal of 4 , from which it was deduced that both 3 and 5 are α- D -fructofuranosides.

Synthesis and structure of 2-t-butylcyclohexane-1,3-dione

2-t-Butylcyclohexane-1,3-dione has been prepared; spectral studies suggest that it exists exclusively as the keto-tautomer (1a).

Aromatic proton magnetic resonances that are not shifted by Eu(dpm)3

The failure of the meta and para-proton magnetic resonances of cis-4-t-butyl-1-phenylcyclohexanol to shift in the presence of added Eu(dpm)3 indicates a limit in the precision with which conclusions drawn from shift-reagent analysis can be specified.