Rodger L. Foltz

Analysis of sugar derivatives by chemical-ionization mass-spectrometry

Abstract D -Glucose diethyl dithioacetal ( 1 ), its penta- O -acetyl derivative ( 2 ), penta- O -acetyl- aldehydo - D -glucose ( 3 ), L - xylo -hexulose phenylosotriazole ( 4 ), 1,2:5,6-di- O -isopropylidene- D -mannitol ( 5 ), 1,2:4,5-di- O -isopropylidene-β- D -fructopyranose ( 6 ), 1,2- O -isopropylidene-α- D -glucofuranose ( 7 ) and its triacetate ( 8 ), 1,6-anhydro-β- D -galactopyranose ( 9 ) and its triacetate ( 10 ), D -glucopyranose ( 11 ), methyl β- D -glucopyranoside tetraacetate ( 12 ), 1-thio-β- D -glucopyranose pentaacetate ( 13 ), β- D -fructofuranose pentaacetate ( 14 ), and raffinose hendecaacetate ( 15 ) have been examined by chemical-ionization mass-spectrometry with both isobutane and ammonia as ionizing intermediates. Extreme simplicity characterizes these spectra, and, in most instances, molecular-weight data are available from intact, protonue5f8or NH 4 + ue5f8capture ions; the limited fragmentation that occurs corresponds in large measure to simple dehydration or substituent-cleavage processes, and is strongly dependent upon the groups present, so that considerable information about the substituent groups in the sugar molecule may be inferred.

Chemical-ionization mass spectrometry of carbohydrates: Behavior of the antibiotic celesticetin under various conditions of ionization

Abstract The chemical-ionization mass spectrum of the polyfunctional carbohydrate antibiotic, celesticetin, is remarkably simple, in contrast to its electron-impact mass spectrum. With ammonia as the ionizing gas the protonated molecular ion is the principal species, and simple fragmentation modes reflect eleavage between principal moietics of the molecule. Substantial modifications of the fragmentation pathway are observed when isobutane is used as the ionizing gas. The different pathways of fragmentation according to the mode of ionization are interpreted in terms of differential reactivity of various heteroatomic centers in the molecule toward each of the ionizing agents. Use of a combination of ionizing modes may provide a useful general method for identification on a micro scale of complex carbohydrates isolated from fermentation or other mixtures.

Analysis of benzoylecgonine in urine by high-performance liquid chromatography and gas chromatography-mass spectrometry.

Benzoylecgonine, a polar metabolite of cocaine, was extracted and purified from urine using a reversed-phase high-performance liquid chromatographic column. The portion of the eluent corresponding to elution of the drug was collected, derivatized, and quantified using gas chromatography-mass spectrometry with selected ion monitoring. Using this procedure, analysis of 1 ng/ml of benzoylecgonine in urine can be achieved.

Chemical-ionization mass spectrometry of lincomycin and clindamycin.

Abstract The chemical-ionization (ci) mass spectra of the carbohydrate antibiotic lincomycin (1), its 7(S)-chloro analog clindamycin (2), and its N-deacylated derivative methyl 1-thiolincosaminide (3), produced with isobutane or ammonia as the reagent gas, display in each instance the protonated molecular-ion as the most abundant species. Only a few fragment-ions are observed, and these arise largely from low-energy, nonskeletal cleavage-reactions of the major ion, or through thermal breakdown of the original molecule; characteristic differences in the patterns of charge capture are observed as a function of the reagent gas. The spectra contrast sharply with those obtained by electron-impact (ei) mass spectrometry, wherein extreme fragmentation occurs and few prominent fragments of high mass are observed. The ci-ms technique offers considerable potential as a micro method for determining the purity of antibiotics, for analyzing them in admixture, and for monitoring reactions performed by chemical or biochemical methods to effect structural modification of antibiotics.

Chemical ionization mass spectra of macrolide antibiotics

Chemical ionization mass spectrometry is shown to be a valuable tool for structural analysis of certain macrolide antibiotics.

Fragmentation process occurring in proton-transfer chemical-ionization mass spectrometry

The isobutane chemical-ionization mass spectra of deuterium-labelled model compounds show that fragmentation can occur at locations remote from the site of protonation.