Danny J. Harvey

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Electrospray ionization-ion trap mass spectrometry, with its capacity to perform multiple stages of fragmentation (MSn), is demonstrated as an effective method for the structural characterization of permethylated N-linked complex glycoprotein oligosaccharides. Complex glycan structural features, such as N-acetyllactosamine antenane, neuraminic acids, and(More)
Comparative studies of the matrix-assisted laser desorption ionization of complex oligosaccharides were made using a range of mono, di- and tri-substituted benzoic acids, substituted coumarins and cinnamic acids. The best results were obtained with 2,5-dihydroxybenzoic acid (2,5-DHB). Detection limits using this matrix were in the range of 100 fmol for(More)
The use of electrospray ionization-quadrupole ion trap mass spectrometry for the characterization of linear oligosaccharides and N-linked protein oligosaccharide mixtures is described. Tandem mass spectrometry (MS/MS) experiments with orders higher than two offer a number of ways to enhance MS/MS spectra and to derive information not present in MS and MS2(More)
Deuterium labelling and high resolution mass measurements have been used to investigate the fragmentation mechanisms leading to diagnostic ions in the mass spectra of the trimethylsilyl derivatives of 58 hydroxy and acid metabolites of delta 1- and delta 6-tetrahydrocannabinol and of two related compounds, 2 alpha- and 2 beta-hydroxy-delta(More)
The mechanisms leading to the major ions in the mass spectra of the trimethylsilyl derivatives of cis- and trans-hexahydrocannabinol, five monohydroxy analogues, eight dihydroxy analogues, and two carboxylic acid derivatives were investigated with the aid of deuterium labelling and high resolution mass measurements.
The 25 eV mass spectra of the trimethylsilyl derivatives of a number of 6-hydroxy and 3,6-dihydroxy steroids together with deuterium and 18O-labeled analogs have been examined to determine the influence of the 6-OTMS group on fragmentation patterns. Ions in the cholestane series at m/z 321 and 403 were the most characteristic ions derived from the 6-OTMS(More)
The preparation and gas chromatographic mass spectrometric properties of a number of vinyldimethylsilyl ethers of steroids and cannabinoids are reported. Gas-liquid chromatographic retention increments for the vinyldimethylsilyl ethers were about 1 methylene unit higher than those of the corresponding trimethylsilyl ethers for each derivatized hydroxyl(More)
The cleavage of the C-17--C-20 bond in the trimethylsilyl derivatives of C21 steroids has been investigated with the aid of isotopic labelling. A significant amount of reciprocal exchange was observed between trimethylsilyl groups or hydrogen atoms on the 20-O- and 17-O-positions. The loss of positional identity of these groups was found to influence the(More)
Stable cyclic methyl- and n-butylboronates were prepared from the cannabinolic acids and used as derivatives for the characterization of these compounds by combined gas chromatography mass spectrometry. Retention times of the methylboronates were comparable with those of the trimethylsilyl derivatives. The mass spectra of these derivatives were more(More)