Gas analysis by modulated molecular beam mass spectrometry

Abstract

A system for mass spectrometric determination of trace constituents .in gases which uses a molecular beam inlet system was built and tested. Modulation of the sampling molecular beam permitted the use of phase sensitive detection methods, which improved the signal-to-noise ratio and reduced the interference caused by background gases in the vacuum chamber. The system was tested by analyzing natural oxygen gas for the various isotopic combinations. The 1.5-ppm 1 7 0 1 8 0 isotope was measured with a relative error of 5%. The ultimate sensitivity of the technique is believed to be approximately 0.1 ppm.THE SENSITIVITY of mass spectrometric analyses for trace constituents in gases is often limited by the pressure of the back-24/40 fitting Collar-I8mm 0.d.

Decision letter for "Investigating the fragmentation pathways of β-naphthol pigments by Liquid Chromatography - Electrospray Ionization Quadrupole Time-of-Flight Mass Spectrometry"

“…Mass spectrometry measurement in which the sample is introduced into the ion source of the mass spectrometer as a collimated beam of molecules with a narrow velocity distribution. From [237].…”

Mass spectrometry

“…Another system has been described for introduction into a mass spectrometer of a sample in the form of a molecular beam (1567). A system for massspectrometric determination of trace constituents in gases, which uses a molecular-beam inlet system, has been built and tested (1568). Ammoniaborane and aminoborane vapors (1569) and octaborane [18] (1570) have been investigated by molecular-beam mass spectrometry.…”