| Résumé | Development and initial characterization of FAPES as an ion source for elemental mass spectrometry is presented. The source is configured with an integrated contact cuvette in which a 40 MHz He plasma is sustained at atmospheric pressure. A differentially pumped interface consisting of a stainless steel sampling tube (0.5 mm i.d.) and tandem skimmer cone serves to sample the plasma from the open end of the cuvette. Mass spectra, characterizing plasma species with the furnace at ambient and elevated temperatures, are relatively structureless and show no evidence of He+, He2+, or carbonaceous ions. Transient ion signals, generated during the atomization of a number of analytes introduced in solution form, reveal that the plasma contains sufficiently energetic species to ionize elements having ionization potentials as high as 10.45 eV (iodine). Significant ionization does not occur in the absence of the plasma, nor in the extraction interface. Using Pb as a test element, acceptable isotopic abundances can be obtained, with an estimated absolute limit of detection of 10 pg (2 ng/mL relative). Future directions are discussed. |
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