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From the results of their studies, the authors also claimed that small-bore columns could be used
satisfactorily with the interface without degrading the resolution of the column and, at the same time,
provide good quality mass spectra. They also claimed detection limits of 40 pg and linear dynamic
ranges extending over four orders of magnitude.
Fan et al. [11] developed a belt interface system for LC/MS that could provide both secondary ion mass
spectra and laser desorption mass spectra. A diagram of the dual ionization source is shown in Figure
9.15.
Figure 9.15
The Dual Ionization Transport Interface
T. P. Fan, A. E. Schoem, R. G. Cooks and
P. H. Hemberger, J. Am. Chem. Soc., 103(1981)1295.
Copyright 1981 American Chemical Society
The apparatus consists of a quadrupole mass spectrometer with a moving belt which is used in
conjunction with a Finnigan/ INCOS data system. Samples are deposited on the belt by a type of
thermospray process. Both the ion beam and the laser light are so aligned as to strike the belt at 45° to
the surface, and normal to each other. Xenon gas, ionized by electron impact, is used as the source of
primary ions, which are focused by an
