Phase identification filaments

E. D. Lee, J. D. Henion, C. A. Brunner, I. W. Wainer, T. D. Doyle, and J. Gal, High-performance liquid chromatographic chiral stationary phase separation with filament on thermospray mass spec-trometric identification of the enantiomer contaminant (S)-( + )meth-amphetamine, Anal. Chem., 55 1349 (1986). 

Electron ionization is the most commonly method used for the analysis of volatile compounds. It is the case for organic molecules. This is a ionization in the gas phase that occurs in the ion source by the collision of the neutral molecules of the sample and electrons emitted from a filament by a thermoionic process (Figure 16.17). The ejection of the most weakly held electron leads to positive ions. This reproducible procedure facilitates the identification of a compound by comparing its spectrum with those collected in a spectral library, assuming the compound is registered within. 

In thermolysis FTIR the sample (typically 200 /ug) is loaded onto a quartz boat, which is inserted straight into a platinum coil filament. With the beam focused several mm above the filament surface, the IR-active gas products from the fast heated sample can be detected in near real-time. Fast thermolysis/FTIR spectroscopy combines rapid-scan FTIR (20 scans/s) with pyrolysis of a material and realtime measurement of the gas spectra [376]. Temperature, mass changes and spectral data of IR active gases are thus measured simultaneously as a function of time during the rapid heating phase. High-resolution vapour phase libraries are used for identification. 

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