Hobbs S E, Olesik J W
Department of Chemistry, Venable Laboratory, University of North Carolina, Chapel Hill 27599-3290.
Anal Chem. 1992 Feb 1;64(3):274-83. doi: 10.1021/ac00027a007.
ICPMS signal fluctuations, in some cases larger than 1 order of magnitude, are observed on a tens of microsecond time scale. The analyte ICPMS signal fluctuations are larger than those characteristic of analyte ion emission intensities observed from the side of the plasma. The analyte, solvent and plasma gas ICPMS signal fluctuations correlate with atom and ion emission intensities monitored 1.3 mm in front of the sampling cone. Analyte and O+ ICPMS signals are depressed near incompletely desolvated droplets and enhanced near vaporizing analyte particles. ICPMS molecular ion signals including ArH+, O2+, H2O+, and H3O+ are enhanced near both incompletely desolvated droplets and vaporizing particles. In contrast to other species, Ar+ ICPMS signals are depressed near a vaporizing particle. The nature of the ICPMS signal fluctuations (spikes or dips) observed at a fixed sampling position (sampling depth) is critically dependent on the center (nebulizer) gas flow rate.
