Effects of the sampling interface in MC-ICP-MS: Relative elemental sensitivities and non-linear mass dependent fractionation of Nd isotopes

Newman, Karla

doi:10.1039/c1ja10222b

Cited by 80 publications

(108 citation statements)

References 35 publications

Supporting

Mentioning

105

Contrasting

Order By: Relevance

“…However, the actual reason for the observed MIF remains unknown. 31 As mentioned before, Newman et al 12 and Newman 13 observed MIF depending on the use of different cone geometries. Shirai and Humayun described the evidence of an odd-even isotope separation in tungsten isotopic analysis depending on the type of cones used, as well.…”

Section: Instrumental Isotopic Fractionation In Icp-msmentioning

confidence: 88%

Instrumental Isotopic Fractionation

Irrgeher

Prohaska

2014

Sector Field Mass Spectrometry for Elemental and Isotopic Analysis

View full text Add to dashboard Cite

In mass spectrometry, the term ‘instrumental isotopic fractionation’ is recommended to describe the sum of the effects in a mass spectrometer occurring during sample introduction, ion formation, ion extraction, ion separation and ion detection leading to a difference of the measured isotope ratio from the true isotope ratio in a sample. Instrumental isotopic fractionation (IIF) describes the instrumental fractionation between nuclides of the same element resulting in erroneous results of isotope ratios. The major aspects of IIF for the different techniques (i.e. (LA)-ICP-MS, GDMS, TIMS, SIMS and IRMS) based on magnetic sector field analysers are presented. A special focus is set on the description of the major causes of IIF, the areas of occurrence in the respective instrumentations as well as the impact of IIF on the final measurement result and the related measurement uncertainty. The described techniques differ strongly in the extent of IIF, mainly due to the different ionization sources as well as vacuum conditions.

show abstract

Section: Instrumental Isotopic Fractionation In Icp-msmentioning

confidence: 88%

Instrumental Isotopic Fractionation

Irrgeher

Prohaska

2014

Sector Field Mass Spectrometry for Elemental and Isotopic Analysis

View full text Add to dashboard Cite

show abstract

“…3,32 Different sample and skimmer cone combinations behave differently on the instrumental mass fractionation and nonlinear mass bias because of the geometry, construction and material of the cones. 26,29 Kimura et al 26 found that a low-oxide molecular interface setup (normal sample and skimmer cones with the GE-off mode) required no external mass bias correction (standardless analysis) for Sm and Nd isotope analyses with a sacrice of the instrumental sensitivity by $70%. 26,29 Kimura et al 26 found that a low-oxide molecular interface setup (normal sample and skimmer cones with the GE-off mode) required no external mass bias correction (standardless analysis) for Sm and Nd isotope analyses with a sacrice of the instrumental sensitivity by $70%.…”

Section: Introductionmentioning

confidence: 99%

In situ Nd isotope analyses in geological materials with signal enhancement and non-linear mass dependent fractionation reduction using laser ablation MC-ICP-MS

Zhang

et al. 2015

J. Anal. At. Spectrom.

View full text Add to dashboard Cite

To improve the precision and accuracy of in situ Nd isotope analyses in geological samples, high analytical sensitivity and minimized non-linear mass dependent fractionation are desirable. In this study, we investigated the effects of three different cone combinations and the addition of N 2 with the guard electrode, either grounded or floating, on the performance of Nd isotope analyses. Signal enhancements (2.5-3 folds) were observed for the Jet sample cone + X skimmer cone and for the standard sample cone + X skimmer cone, which were compared to those of the standard sample cone + H skimmer cone with the addition of N 2 at 3 or 6 ml min À1 . The influence of a guard electrode on the LA-MC-ICP-MS sensitivity was minimal for dry plasma conditions but became significant in the presence of N 2 . The addition of 3 or 6 ml min À1 N 2 into the carrier gas increased the sensitivity for Nd by a factor of 1.6 with the GE-on mode for the Jet sample cone + X skimmer cone. However, in the GE-off mode, the addition of 2-3 ml min À1 N 2 decreased the signal intensity of Nd by a factor of two to three. The makeup gas flow rate was found to have a significant effect on the mass bias stability of Nd isotopes, and this effect was different for different cone combinations. To stabilize the mass bias, measurements at elevated makeup gas flow rates was required for the combination of the X skimmer cone with the standard sample cone or Jet sample cone, at the expense of sensitivity. In notable contrast, the mass bias was stable for the combination of the standard sample cone and H skimmer cone under their corresponding optimum makeup gas flow rates. However, we found that the neodymium isotopes exhibited a large non-linear component at elevated makeup gas flow rates that could not be corrected by the accepted mass fractionation laws. The addition of 3-6 ml min À1 nitrogen to the central gas flow in laser ablation MC-ICP-MS was found to not only significantly enlarge the mass bias stability zone, but also to suppress the non-linear mass dependent fractionation for the combination of X skimmer cone with Jet sample cone or standard sample cone. The accuracy and precision of the developed analytical method for Nd isotope using Jet sample cone + X skimmer cone with the addition of nitrogen has been demonstrated by analyzing a series of reference glasses (JNdi-1 glass, LREE glass, NIST 610) and minerals (apatite, monazite and titanite). Results obtained for 143 Nd/ 144 Nd ratios in these reference materials are in excellent agreement with published values, demonstrating the capability of the developed analytical method to be an important tool for providing high-quality in situ Nd isotope data in geological samples.

show abstract

“…To this end, a number of recent studies have looked at increasing 45 the ion sampling efficiency from the ICP source into the mass spectrometer through the use of modified skimmer and sample cone geometries [1][2][3][4] , which are often used in combination with enhanced interface pumping configurations. One area of development is improving the overall sensitivity of the technique to reduce the sample quantities needed for accurate and precise isotope ratio measurements.…”

Section: Introduction 40mentioning

confidence: 99%

The effect of hydride formation on instrumental mass discrimination in MC-ICP-MS: a case study of mercury (Hg) and thallium (Tl) isotopes

Georg

Newman

2015

J. Anal. At. Spectrom.

Self Cite

View full text Add to dashboard Cite

Here we report evidence for enhanced hydride formation for Hg isotopes when using high sensitivity X skimmer cones and the Neptune MC-ICP-MS. The effect on the instrumental mass discrimination and the robustness of the Tl external mass-bias 20 correction was investigated. A series of experiments have been conducted to study the effect of variable Hg concentrations on the measured mass bias correction factor, ! Tl .The results of our experiments show a linear relation between the Hg concentration and the measured 205 Tl/ 203 Tl ratio of the internal standard. The resulting mass-bias correction factor ! Tl thus appears to be dependent on the analyte concentration, 25 questioning the applicability of Tl as an internal standard for high precision Hg isotope ratio measurements. These observations are consistent with the formation of Hg hydrides (HgH x where x = 1, 2). Numerical simulations show Hg hydride formation rates of 0.02 to 0.18% to be consistent with experimental observations, when using high-sensitivity X skimmer cones. Here we discuss the implications of Hg 30 hydride formation for Hg isotope ratio measurements and propose a set of precautionary steps that can help to identify and remediate analytical issues related to hydride formation. Whilst the effect of hydride formation on mass-dependent Hg isotope ratios can be controlled, mass independent Hg ratios are shown to be very sensitive to hydride formation. A comparison between different types of sediment 35 samples and standards also suggests a matrix dependency on hydride formation. We conclude that precise and accurate Hg isotope ratio determination using MC-ICP-MS is possible, however, probably not to low ppm-levels of precision.

show abstract

Effects of the sampling interface in MC-ICP-MS: Relative elemental sensitivities and non-linear mass dependent fractionation of Nd isotopes

Cited by 80 publications

References 35 publications

Instrumental Isotopic Fractionation

Instrumental Isotopic Fractionation

In situ Nd isotope analyses in geological materials with signal enhancement and non-linear mass dependent fractionation reduction using laser ablation MC-ICP-MS

The effect of hydride formation on instrumental mass discrimination in MC-ICP-MS: a case study of mercury (Hg) and thallium (Tl) isotopes

Contact Info

Product

Resources

About