Capabilities of sequential and quasi-simultaneous LA-ICPMS for the multi-element analysis of small quantity of liquids (pl to nl): insights from fluid inclusion analysis

Abstract

International audienceThree configurations of inductively coupled plasma mass spectrometers (ICPMS), namely: a quadrupole (QMS) and a sector-field (SFMS), both equipped with a standard cylindrical ablation cell, and an orthogonal time-of-flight (TOFMS), equipped with a fast washout ablation cell, were coupled with the same 193 nm Excimer laser ablation system in order to evaluate their capabilities for measurement of multiple minor and trace elements in small quantities of liquids (pl to nl), such as fluid inclusions. Analyses were performed with different objects: (i) multi-element solutions sealed in silica capillaries of internal diameter of 20 mm serving as synthetic analogues of natural fluid inclusions; (ii) natural two-phase (liquid + vapour) fluid inclusions with low salinity (ca. 4.8 wt% NaCl eq.) and homogeneous compositions, trapped in quartz crystals from the Alps; (iii) natural multi-phase (liquid + vapour + multiple solids) fluid inclusions with high salinity (ca. 13-15 wt% NaCl eq.) and homogeneous compositions, trapped in quartz crystals from the Zambian Copperbelt. This study demonstrates that the SFMS and TOFMS provide improvements, particularly in term of limits of detection (LODs) and precision, compared to the QMS traditionally used for the measurement of fluid inclusions. SFMS leads on average to lower LODs within one order of magnitude compared to QMS and TOFMS, but precision and accuracy are lower due to longer acquisition cycle times. TOFMS presents both advantages of having rapid and quasi-simultaneous acquisition for all isotopes from Li-6 to U-238 in a very short cycle time down to 30 ms, with higher precisions and lower LODs than for QMS for isotopes with m/Q > 11. Its use, coupled to a fast washout cell, leads to (i) the improvement in the analysis of small-size (<10 mu m) and multi-phase fluid inclusions and (ii) detection of higher number of isotopes compared to QMS and SFMS, which are both limited by the number of measured isotopes from short transient signals of fluid inclusions. Consequently, the tested TOFMS, coupled with a fast washout ablation cell, appears to be a promising instrument for the analysis of natural fluid inclusions by LA-ICPMS, especially for small, multi-phase and/or low salinity fluid inclusions

Microanalysis of Fluid Inclusions in Crustal Hydrothermal Systems using Laser Ablation Methods

“…1). This novel technique has great potential for the next level of fluid inclusion microanalysis (Harlaux et al 2015), particularly if applied to small inclusions in combination with laser sampling cells with shorter wash-out times.…”

Considerations on data acquisition in laser ablation-inductively coupled plasma-mass spectrometry with low-dispersion interfaces

“…[2] Quasi-simultaneous mass spectrometers equipped with detectors with low signal rise times, e.g., time-of-flight mass spectrometers, suffer much less from these sampling artefacts. [3] Most currently available LA-systems are capable of producing a signal peak for a single laser shot with a full width at 1% of the maximum of < 200 ms. [4,5] This means that the response for single shots at frequencies ≤ 5 can be resolved. Thus, a response for each individual pixel (laser shot) in a LA-ICP-MS map can be acquired separately, resulting in spatially resolved pixels.…”

Chemical composition of fluid inclusions in the Yorii jadeite–quartz rocks from the Kanto Mountains, Japan

“…Thus, microanalysis of individual fluid inclusion has been focused to obtain chemical composition of each fluid inclusion using various methods such as proton induced X-ray emission analysis (PIXE), laser ablationinductively coupled plasma-atomic emission spectroscopy (ICP-AES), laser induced breakdown spectroscopy (LIBS), secondary ion mass spectrometry (SIMS), and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). In particular, LA-ICP-MS is a powerful and efficient multi-element microanalytical technique for fluid inclusions because of high analytical sensitivities and wide dynamic range of ICP-MS. A number of studies of fluid inclusion have been performed using LA-ICP-MS since 1990s and continuously improved (e.g., Audétat et al, 1998;Günther et al, 1998;Heinrich et al, 2003;Pettke et al, 2012;Harlaux et al, 2015).…”