Particle beam liquid chromatography—mass spectrometry on a double-focusing sector instrument

• Published in: Journal of chromatography Vol. 562; no. 1; pp. 13 - 29
• Main Author: Baczynskyj, L.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 02.01.1991; Elsevier
• Subjects: Amino Acids - analysis; Analytical biochemistry: general aspects, technics, instrumentation; Analytical, structural and metabolic biochemistry; Biological and medical sciences; Cholesterol - analysis; Chromatography, High Pressure Liquid - instrumentation; Electrochemistry; Fundamental and applied biological sciences. Psychology; Indicators and Reagents; Mass Spectrometry - instrumentation; Methanol; Peptides - analysis; Phenylthiohydantoin - analogs & derivatives; Phenylthiohydantoin - analysis; Spectrophotometry, Ultraviolet; Steroids - analysis
• ISSN: 0378-4347
• DOI: 10.1016/0378-4347(91)80560-Y

A commercially available particle beam interface developed by the Vestec Corporation has been coupled to a double-focusing high-resolution mass spectrometer (VG ZAB 2F) via a momentum separator. An ultraviolet detector was in-line with the interface and allowed monitoring of the eluting materials. With this instrumentation, complete electron-impact (EI) mass spectra on synthetic mixtures of steroids, nucleosides, and several derivatives of amino acids were recorded. Amongst these the EI mass spectra of 2,4-dinitrophenyl, 9-fluorenylmethoxycarbonyl and phenylthiohydantoin derivatives were obtained. The standard LC conditions used here (250 mm × 4.6 mm I.D., reversed-phase C 18 column, 1.0 or 1.5 ml/min flow-rate, isocratic or gradient programming) allowed separation of the mixtures. The resulting mass spectra were compared with those obtained using a direct insertion probe. The agreement was excellent in most cases. Sensitivity measurements were performed on cholesterol and caffeine. A complete low-resolution mass spectrum can be obtained on 100 ng of cholesterol. Single-ion monitoring of the M + of 200 pg of caffeine gave a 4:1 signal-to-noise ratio at m/z 194. Complete high-resolution mass spectra were obtained on 5 μg of cholesterol (loop injection) and on every peak of a five-steroid mixture of 5 μg each. The accuracy of the mass measurements were better than 5 m.m.u. for most cases. Three to four scans could be obtained for each liquid chromatographic peak. Mass-analyzed ion kinetic energy spectra were recorded on the M + of 2.5 μg of cholesterol at m/z 386. Similarly the B/E linked scan of the same ion was recorded on 2.5 μg and 500 ng.