Organic elemental analysis

Isotope-ratio-monitoring gas chromatography-mass spectrometry

“…To measure the efficiency of the cupric oxide-filled combustion oven, methane was injected into the GC and masses 15 and 44 were monitored on alternate injections (mass 15, which carries about 40% of the total ion current in the spectrum of CH4, was used to monitor methane because oxygen from the hot cupric oxide interfered at mass 16). Knowing the ratio of combusted methane (carbon dioxide, mass 44) to noncombusted methane (mass 15) and considering the fraction of the total C02 ion current at mass 44 and the fraction of the total CH4 ion current at mass 15, the combustion efficiency of the oven could be calculated.…”

“…Although the impurity had escaped notice in a number of routine reaction-monitoring analyses, the 13C-carboxylated product is hard to miss in the IRM-GCMS ratio plot. Quantitatively, the sensitivity of IRM-GCMS as a technique for detecting 13C-labeled compounds can be judged by noting that the C9 peak corresponds to 1.3 nmol of ester while the C10 peak represents only 16 pmol of ester. In this case, because R* » fibkgd-a minor impurity has become visible even though g(t) < b.…”

Organic elemental analysis

“…This review covers the published literature from July 1975 to July 1977 although a few citations of other work are also included. As the previous reviewer observed (1) the volume of literature in which electron spin resonance (ESR) information is contained is too extensive for even brief citations in a review of this nature. However, it is hoped that the publications cited do provide a useful guide to recent developments and applications of ESR spectroscopy to chemical systems.…”