Quantitative analysis using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) remains challenging primarily due to elemental fractionation effects and to the lack of appropriate standards available for the wide variety of samples of interest and. Isotopic dilution mass spectrometry (IDMS) is becoming the methodology of choice to address these issues because the different isotopes of an element represent near-perfect internal standards. In this work, we investigated the lithium borate fusion of powdered solid samples, including soils, sediments, rock mine waste and a meteorite, as a strategy to homogenously distribute the elements and the added isotopically-enriched standards. A comparison of this methodology using two pulsed laser ablation systems (ArF* excimer and Nd:YAG) with different wavelengths as well as two ICP-MS instruments (quadrupole and double-focusing sector field) was performed. Emphasis was put on using standard equipment to show the potential of the proposed strategy for its application in routine laboratories. Cr, Zn, Ba, Sr and Pb were successfully determined by LA-ICP-IDMS in six Standard Reference Materials (SRMs) representing different matrices of environmental interest. Experimental results showed the SRM fused glasses exhibited a low level of heterogeneity (intra- and inter-sample) for both natural abundance and isotopically-enriched samples (RSD values below 3%). A good agreement between experimental results and the certified values was also observed.
Citation: Chemical Geology
Pub Type: Journals
Laser ablation, Trace element ICP-MS, Isotope dilution mass spectrometry, Geological reference materials