The use of a sampler-skimmer interface for ion sampling in furnace atomization plasma ionization mass spectrometry

Improvements to the FAPES-mass spectrometer interface permit high-sensitivi ty 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 He-2(+), C+, N+, O+, NH4+, H3O+, N-2(+), and O-2(+) and carbonaceous i ons. Transient ion signals, generated during the atomization of a number of anafytes introduced in solution form, reveal that the plasma contains suff iciently energetic species to ionize and determine elements having ionizati on potentials as high as 9.75 eV (Se), Figures of merit, including the esti mated absolute limits of detection, measurement precision, isotope ratio me asurements, and linear dynamic range, are discussed. In general, the measur ement precision is similar to 5% and the absolute limits of detection range from 20 to 500 fg for Mg, Fe, Co, Cu, Se, Cd, Cs, and Pb.