Origins of polyatomic ions in laser ablation-inductively coupled plasma-mass spectrometry: An examination of metal oxide ions and effects of nitrogen and helium in the aerosol gas flow

Witte, Travis M.; Houk, R. S.

doi:10.1016/j.sab.2012.02.005

Cited by 22 publications

(16 citation statements)

References 59 publications

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“…Witte et. al. reported 50% gains in MS signals when adding He [6]. We concluded that more efficient transport through the interface in the presence of helium could account for the 2 apparent inconsistency of the decrease ion signal we observed with improved sensitivities generally reported.…”

Section: Introductionmentioning

confidence: 57%

The effects of He on ablation and inductively coupled plasma environment in ultra-violet, nanosecond laser ablation inductively coupled plasma mass spectrometry

Moses

Farnsworth

2015

Spectrochimica Acta Part B: Atomic Spectroscopy

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The effects of helium gas on ablation and ICP processes were investigated. Differences in the size, shape, and abundance of aerosol particles generated in argon and helium atmosphere were studied off-line using SEM imaging of aerosol particles impacted on polycarbonate filter disks. In general, ablation in helium generated fewer large particles, and larger, more densely-packed softagglomerates. However, corresponding changes in the ion densities in the ICP, observed in high-resolution images obtained using LIF, were not always predictable. In all cases, higher He/Ar ratios led to lower ion densities in the ICP. This effect was attributed to increased rates of off-axis diffusion at higher He/Ar ratios. Differences in the ion densities produced during ablation in argon vs helium were highly dependent on sample type, the axial position of vaporization, and the He/Ar ratio. There was evidence that vaporization efficiencies of softagglomerates were less affectedthan micron-sized particles by particle acceleration at higher He/Ar ratios.

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Section: Introductionmentioning

confidence: 57%

The effects of He on ablation and inductively coupled plasma environment in ultra-violet, nanosecond laser ablation inductively coupled plasma mass spectrometry

Moses

Farnsworth

2015

Spectrochimica Acta Part B: Atomic Spectroscopy

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“…Finally, for T gas ≫6000 K, these polyatomic ions are less abundant than expected from the ICP and are thus removed during the extraction process. Weakly bound Ar adduct ions like MAr + for M=transition metals are typical of this latter case …”

Section: Figurementioning

confidence: 96%

“…The measured signal ratios for MAr + /M + and MAr 2+ /M 2+ can be used to calculate apparent values for gas kinetic temperature T gas at which they form. The methods are described in detail elsewhere . Basically, dissociation reactions involving a particular pair of ions are written [Eqs.…”

Section: Figurementioning

confidence: 99%

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Mass Spectrometric Observation of Doubly Charged Alkaline‐Earth Argon Ions

et al. 2016

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Doubly charged diatomic ions MAr(2+) where M=Mg, Ca, Sr or Ba have been observed by mass spectrometry with an inductively coupled plasma ion source. Abundance ratios are quite high, 0.1 % for MgAr(2+) , 0.4 % for CaAr(2+) , 0.2 % for SrAr(2+) and 0.1 % for BaAr(2+) relative to the corresponding doubly charged atomic ions M(2+) . It is assumed that these molecular ions are formed through reactions of the doubly charged metal ions with neutral argon atoms within the ion source. Bond dissociation energies (D0 ) were calculated and agree well with previously published values. The abundance ratios MAr(+) /M(+) and MAr(2+) /M(2+) generally follow the predicted bond dissociation energies with the exception of MgAr(2+) . Mg(2+) should form the strongest bond with Ar [D0 (MgAr(2+) )=124 to 130 kJ mol(-1) ] but its relative abundance is similar to that of the weakest bound BaAr(2+) (D0 =34 to 42 kJ mol(-1) ). The relative abundances of the various MAr(2+) ions are higher than those expected from an argon plasma at T=6000 K, indicating that collisions during ion extraction reduce the abundance of the MAr(2+) ions relative to the composition in the source. The corresponding singly charged MAr(+) ions are also observed but occur at about three orders of magnitude lower intensity than MAr(2+) .

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“…In addition to being shifted upstream relative to the SN profiles, the LA profiles rise more gradually. The change in the profile shape could be a reflection of reduced oxide formation during LA [32][33][34], or it could be due to a shift in the particle size distribution to favor smaller particles.…”

Section: Solution Nebulization Vs Laser Ablationmentioning

confidence: 99%

Fluorescence imaging of ion distributions in an inductively coupled plasma with laser ablation sample introduction

Moses

Ellis

Jones³

et al. 2015

Spectrochimica Acta Part B: Atomic Spectroscopy

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a b s t r a c tHigh-resolution images of the spatial distributions of Sc II, Ca II, and Ba II ion densities in the 10 mm upstream from the sampling cone in a laser ablation-inductively coupled plasma-mass spectrometer (LA-ICP-MS) were obtained using planar laser induced fluorescence. Images were obtained for each analyte as a function of the carrier gas flow rate with laser ablation (LA) sample introduction and compared to images with solution nebulization (SN) over the same range of flow rates. Additionally, images were obtained using LA at varying fluences and with varying amounts of helium added to a constant flow of argon gas. Ion profiles in SN images followed a pattern consistent with previous work: increasing gas flow caused a downstream shift in the ion profiles. When compared to SN, LA led to ion profiles that were much narrower radially and reached a maximum near the sampling cone at higher flow rates. Increasing the fluence led to ions formed in the ICP over greater axial and radial distances. The addition of He to the carrier gas prior to the ablation cell led to an upstream shift in the position of ionization and lower overall fluorescence intensities.

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Origins of polyatomic ions in laser ablation-inductively coupled plasma-mass spectrometry: An examination of metal oxide ions and effects of nitrogen and helium in the aerosol gas flow

Cited by 22 publications

References 59 publications

The effects of He on ablation and inductively coupled plasma environment in ultra-violet, nanosecond laser ablation inductively coupled plasma mass spectrometry

The effects of He on ablation and inductively coupled plasma environment in ultra-violet, nanosecond laser ablation inductively coupled plasma mass spectrometry

Mass Spectrometric Observation of Doubly Charged Alkaline‐Earth Argon Ions

Fluorescence imaging of ion distributions in an inductively coupled plasma with laser ablation sample introduction

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