| Résumé | Improvements to the FAPES−mass spectrometer interface permit high-sensitivity elemental analysis with the FAPIMS ion source. 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 modified sampler cone (0.45-mm i.d.) and tandem skimmer cone (0.88-mm i.d.) serve to sample the plasma from the open end of the cuvette. Mass spectra, characterizing plasma species with the furnace at elevated temperatures, show He2+, C+, N+, O+, NH4+, H3O+, N2+, and O2+ and 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 and determine elements having ionization potentials as high as 9.75 eV (Se). Figures of merit, including the estimated absolute limits of detection, measurement precision, isotope ratio measurements, and linear dynamic range, are discussed. In general, the measurement precision is ∼5% and the absolute limits of detection range from 20 to 500 fg for Mg, Fe, Co, Cu, Se, Cd, Cs, and Pb. |
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