Incompletely desolvated droplets in argon inductively coupled plasmas: their number, original size and effect on emission intensities

Olesik, John W.; Fister, Julius C.

doi:10.1016/0584-8547(91)80086-i

Cited by 119 publications

(55 citation statements)

References 9 publications

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“…This difference is a likely result of the boundary layer at the particle surface, which limits the energy-transfer from the plasma towards the particle [37] and thus reduces the effective surface temperature to below T gas . The "vaporization cloud" [38] surrounding the aerosol particle can further reduce the atomization and ionization efficiencies of vaporized material and cause additional signal suppression.…”

Section: Resultsmentioning

confidence: 99%

Analyte response in laser ablation inductively coupled plasma mass spectrometry

Wang

Hattendorf

Günther

2006

J. Am. Soc. Mass Spectrom.

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The dependence of analyte sensitivity and vaporization efficiency on the operating parameters of an inductively coupled plasma mass spectrometer (ICPMS) was investigated for a wide range of elements in aerosols, produced by laser ablation of silicate glass. The ion signals were recorded for different carrier gas flow rates at different plasma power for two different laser ablation systems and carrier gases. Differences in atomization efficiency and analyte sensitivity are significant for the two gases and the particle size distribution of the aerosol. Vaporization of the aerosol is enhanced when helium is used, which is attributed to a better energy-transfer from the plasma to the central channel of the ICP and a higher diffusion rate of the vaporized material. This minimizes elemental fractionation caused by sequential evaporation and reduces diffusion losses in the ICP. The sensitivity change with carrier gas flow variation is dependent on m/z of the analyte ion and the chemical properties of the element. Elements with high vaporization temperatures reach a maximum at lower gas flow rates than easily vaporized elements. The sensitivity change is furthermore dependent on m/z of the analyte ion, due to the mass dependence of the ion kinetic energies. The mass response curve of the ICPMS is thus not only a result of space charge effects in the ion optics but is also affected by radial diffusion of analyte ions and the mismatch between their kinetic energy after expansion in the vacuum interface and the ion optic settings. T he analytical performance of laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) analysis is determined by the amount and stoichiometry of the laser generated aerosol as well as by the degree of vaporization, atomization, and ionization of this aerosol in the ICP, and finally the transmission of the ions through the vacuum interface and the ion optics of the ICPMS. The parameters used for laser ablation determine the amount, composition, and particle size distribution of the aerosol released for a given sample [1][2][3]. It has been shown that wavelength, pulse duration, and fluence of the laser beam are the dominating parameters that affect the stoichiometry of the aerosol [2, 4 -6]. Nonetheless, it was found that significant variations in the elemental responses for different elements can be obtained for different ICP operating conditions and for different ICPMS systems, even when stoichiometric sampling from homogeneous (on the scale of the laser spot) samples can be achieved [7][8][9]. These results are currently attributed to incomplete vaporization of the aerosol in the ICP. Particularly when silicate samples are ablated, the aerosol may contain a large fraction of refractory particles and agglomerates above 150 nm in diameter, which are not completely atomized under typical ICP-operating conditions [6,10,11].The particle size distribution of the laser generated aerosol is in the first instance the result of a complex interaction of the laser beam with the sample mater...

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Section: Resultsmentioning

confidence: 99%

Analyte response in laser ablation inductively coupled plasma mass spectrometry

Wang

Hattendorf

Günther

2006

J. Am. Soc. Mass Spectrom.

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“…If we compare this value with the data corresponding to S tot (c.a., 10.5 and 21.8 mg min −1 with and without separator, respectively), it was concluded that the mass of solvent transported in liquid form corresponded to the difference between S tot with and without separator. According to theoretical calculations the mass of water that can evaporate inside the spray chamber at 20 • C ranges from 20 to 30 mg L −1 of argon [39]. By taking into account the nebulizer gas flow rate used (i.e., 0.45 L min −1 ), the mass of water that could evaporate was within the 9-14 mg min −1 range.…”

Section: Solvent Plasma Loadmentioning

confidence: 99%