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low flow rates demanded by microbore columns. The system was used to separate and identify a range
of arsenical, animal feedstock additives, from naturally occurring organic and inorganic arsenic
compounds. The microbore column was I m long, I mm I.D., packed with a reversed phase. Two
distribution systems were examined one where the separation was achieved by employing dispersive
interactions only, in conjunction with a mobile phase consisting of 0.1% trifluoroacetic acid and 5%
methanol in water at a flow rate of 40 ml/min. The other was obtained by exploiting a mixture of
dispersive and ionic interactions with the stationary phase, by using an ion pair reagent contained in the
mobile phase, which consisted of 1 mM tetrabutyl-ammonium hydroxide and 5% methanol in deionized
water. The lower limit of detection was reported as 4 ng/l, which would be equivalent to 4 pg/ml. The
volume of sample placed on the column was not clear, but if it were 1 µl, then this would be equivalent
to a mass of 4 fentograms. The high resolution of the liquid chromatograph, coupled with the high
sensitivity of ICP-MS, makes the tandem combination a very powerful tool for use in many
contemporary analytical applications such as this.

The Particle Beam Interface

The particle beam interface involves nebulizing the column eluent, and the solvent free particles of
solute, so produced, are then passed into the ionization chamber of the mass spectrometer. Electron
impact or chemical ionization spectra can be produced, and the system has been given the somewhat
pretentious name of monodisperse aerosol generation interface for chromatography. In addition it has
been endowed with an even more pretentious acronym (MAGIC). Willoughby and Browner [43] and
Winkler et al. [44] were two of the early groups working on this interface which consists of two parts,
the aerosol generator and the momentum separator. A diagram of the aerosol generator described by
Creaser and Stygall [45] is shown in Figure 9.53. Nebulization takes place at the end of a fused silica
tube, 25 µm I.D., made from the same type of tubing employed routinely in capillary gas
chromatography.The liquid jet is formed at the end of the small-diameter tubing, and although simple in
design, is very efficient and seldom clogs. Nevertheless precautions must