Journal of Analytical Atomic Spectrometry 

About: Journal of Analytical Atomic Spectrometry is an academic journal published by Royal Society of Chemistry. The journal publishes majorly in the area(s): Inductively coupled plasma mass spectrometry & Inductively coupled plasma. It has an ISSN identifier of 0267-9477. Over the lifetime, 7409 publications have been published receiving 211838 citations. The journal is also known as: JAAS & JAAS online.

Iolite: Freeware for the visualisation and processing of mass spectrometric data

Abstract: Iolite is a non-commercial software package developed to aid in the processing of inorganic mass spectrometric data, with a strong emphasis on visualisation versus time of acquisition. The goal of the software is to provide a powerful framework for data processing and interpretation, while giving users the ability to implement their own data reduction protocols. It is intended to be highly interactive, providing the user with a complete overview of the data at all stages of processing, and allowing the freedom to change parameters and reprocess data at any point. The program presents a variety of windows for the selection and viewing of data versus time, as well as features for the generation of X-Y plots, summary reports and export of data. In addition, it is capable of generating X-Y images from laser ablation rasters, and combining information from up to four separate elemental concentrations (intensities of red, green and blue, and the z-axis) in a false-colour three-dimensional image. By virtue of its underlying computing environment—Igor Pro—Iolite is capable of processing very large datasets (i.e., millions of timeslices) rapidly, and is thus ideal for the interrogation of multi-hour sessions of laser ablation data that can not be easily manipulated in conventional spreadsheet applications, for example. It is also well suited to multi-day sessions of solution-mode inductively-coupled plasma mass spectrometer (ICPMS) or thermal ionisation mass spectrometer (TIMS) data. A strong emphasis is placed on the interpolation of parameters that vary with time by a variety of user selectable methods including smoothed cubic splines. Data are processed on a timeslice-by-timeslice basis, allowing outlier rejection and calculation of statistics to be employed directly on calculated results. This approach can reduce the risk of processing biases associated with the manipulation of integrated datasets, while also allowing the implementation of more complex data reduction methods.

Inter-laboratory note. Laser ablation inductively coupled plasma mass spectrometric transient signal data acquisition and analyte concentration calculation

Abstract: Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) produces complex, time-dependent signals. These require significantly different treatment both during data acquisition and reduction from the more steady-state signals produced by solution sample introduction. This paper discusses, in detail, data acquisition and reduction considerations in LA-ICP-MS analysis. Optimum data acquisition parameters are suggested. Equations are derived for the calculation of sample concentrations and LOD when time-resolved data acquisition is employed, sensitivity calibration is obtained from reference materials with known analyte concentrations and naturally occurring internal standards are used to correct for the multiplicative correction factors of drift, matrix effects and the amount of material ablated and transported to the ICP.

Hf isotope ratio analysis using multi-collector inductively coupled plasma mass spectrometry: an evaluation of isobaric interference corrections

Abstract: From measurements of Hf–Yb mixtures, we have found that the correction of isobaric interferences involving accepted Yb isotope ratios and reasonable estimates of mass bias result in a significantly under-corrected 176Hf, which is proportional to the amount of Yb added. This can be explained by (1) a significant difference in the instrumental mass bias between Hf and Yb, and (2) that the accepted values for isotopic ratios within the Yb and/or Hf systems are incorrect. We have evaluated these possibilities by measuring mixed solutions of Yb and Hf on two MC-ICP-MS instruments and undertaking a series of REE fractionation experiments using a thermal ionisation mass spectrometer (TIMS). Our results indicate that the presently accepted abundances of the Yb isotopes are not appropriate. We present new values for Yb isotopic abundances based on the TIMS and MC-ICP-MS results. Using the newly defined Yb values, we demonstrate that Yb and Hf have similar levels of mass bias in plasma ionisation instruments, and that Hf isotope ratios can be used to correct Yb mass bias before subsequent correction of isobaric interference. A laser ablation comparison of Yb and Hf indicates that similar relationships exist, and can be applied to micro-analytical techniques where chemical separation is not possible.

Improved in situ Hf isotope ratio analysis of zircon using newly designed X skimmer cone and jet sample cone in combination with the addition of nitrogen by laser ablation multiple collector ICP-MS

Abstract: The effect of three different cone combinations on the performance of laser ablation MC-ICP-MS (Neptune plus) for the in situ Hf isotope analysis of zircon were investigated. The signal sensitivities of Hf, Yb and Lu were improved by a factor of 1.4 and 2.5, respectively, with using the X skimmer cone + standard sampler cone and the X skimmer cone + Jet sample cone compared to the standard arrangement (H skimmer cone + standard sample cone). However, when using the high-sensitivity Jet sample cone, the instrumental mass fractionation for hafnium displayed a large non-linear component that could not be corrected using the normal mass fractionation laws. The magnitude of this non-linear mass fractionation was strongly related to the central gas flow rate. The in situ Hf isotope analysis of zircon standards 91500 and Mud Tank using the Jet cone displayed large deviations (410–470 ppm) at the optimum central gas flow rate for Hf, which seriously deteriorated the performance of the Jet cone. The addition of 4 ml min−1 nitrogen to the central gas flow in laser ablation MC-ICP-MS was found to not only increase the sensitivity of Hf by a factor of 2.1, but also suppress this non-linear mass fractionation. The determined Yb/Hf and Lu/Hf ratios at their corresponding optimum makeup gas flow rates for Hf intensity were found to be reduced by factors of 2 and 1.3 in the presence of nitrogen, respectively, which would benefit the accurate in situ determination of Hf isotopes in high-content Yb and Lu samples. Compared to the standard arrangement, the corresponding precision (2σ) of 176Hf/177Hf for single spot analysis of zircon standard 91500 was improved from 224 ppm to 50 ppm by using the newly designed X-skimmer cone and Jet sample cone in combination with the nitrogen addition technique. The determined 176Hf/177Hf ratios are in excellent agreement with published values in five reference zircon standards (91500, GJ-1, Mud Tank, Penglai and Plesovice). Our first Hf isotopic results from zircon standard M257 (0.281544 ± 0.000018; 2SD, n = 151) showed that it was fairly homogeneous in Hf isotopes. These results clearly demonstrate that the present analytical method has the potential to become an important tool for the pursuit of high-quality in situ Hf isotope data for zircons.

Allanite U–Th–Pb geochronology by ion microprobe

Abstract: Allanite, an epidote group mineral, occurs as a common accessory mineral in igneous, metamorphic rocks and hydrothermal deposits. It contains radioactive elements Th and U, making it a valuable U–Th–Pb geochronometer for various geological processes. Due to the structural and compositional complexity of allanite, in situ dating method is a better choice when the allanite is heterogeneous or has crystallized in multi-stage events. The wide variation of chemical compositions, however, raises the potential for matrix effects and complicates the use of in situ methods for allanite U–Th–Pb chronology. To address this issue, we made a comprehensive investigation on allanite U–Th–Pb chronology using Secondary Ion Mass Spectrometry (SIMS). Five allanite samples (CAP, Daibosatsu, SQ-51, Toba OTT, TARA allanite) with variable elemental compositions and common lead concentrations have been used. Allanites with variations in FeO (from 12.8 to 16.1 wt%) and similar ThO2 contents (around 1–2%) do not show significant matrix effects, as suggested by a previous study. While, obvious changes in calibration parameters (UO2+/U+, ThO2+/Th+) were noticed for allanites with a large range of Th contents (from 300 ppm to 2.0 wt%). By employing power law relationships between Pb+/U+versus UO2+/U+, Pb+/Th+versus ThO2+/Th+ with suitable exponentials, we do not observe obvious matrix effects with ThO2 concentrations variations. This study demonstrates that allanite can be a good geochronometer for multi-stage mineralization of hydrothermal deposits, providing valuable complementary information to zircon and monazite.