A User‐Friendly Workbook to Facilitate Rapid and Accurate Rare Earth Element Analyses by ICP‐MS for Multispiked Samples

Abstract

The rare earth elements (REEs) are widely used as geochemical tracers in the earth, planetary, and ocean sciences. Inductively coupled plasma‐mass spectrometry (ICP‐MS) has become the method of choice to analyze REE concentrations because it can rapidly measure the entire REE spectrum at the same time. This Technical Report presents a user‐friendly “REE Calculation Workbook” in Microsoft Excel to be used for calculating REE abundances in samples equilibrated with a multielement REE spike. This Workbook can be conveniently used to calculate REE concentrations in natural samples for spiked and unspiked elements measured by ICP‐MS. For the spiked elements, their concentrations are calculated using isotope dilution equations. Using these spiked elements as references, concentrations of the four mono‐isotopic REE elements, and other REE elements that are treated as mono‐isotopic elements (in our case, La and Lu), can be calculated. The REE Workbook can be easily set up for use with different REE spikes. Evaluation of our analytical quality using a quadrupole ICP‐MS on 10‐ml‐sized seawater samples shows that our analyses are comparable to high‐precision thermal ionization mass spectrometry (TIMS) studies, with much less time spent processing and analyzing, and with the added advantages of determining mono‐isotopic elements. An important result is the clear demonstration of enrichments in Gd and Er compared to neighboring elements in seawater samples. In addition, we compare and evaluate commonly used reference standards BCR‐1, Post‐Archean Australian Shale (PAAS), and North American Shale Composite (NASC).

Atomic spectrometry update – a review of advances in environmental analysis

“…The geometry of the skimmer cone was crucial to achieving higher sensitivities and the addition of N 2 to the central channel of the plasma reduced oxide formation rates considerably. Wu et al 260 used a multi-REE spike and ICP-MS analysis to generate high-quality REE data that were claimed to be comparable to those obtained using high-precision ID-TIMS but within a few minutes rather than a couple of days. To facilitate calculation of the final data, a “REE Calculation Workbook” based on Microsoft Excel was made available.…”

Assessing neodymium isotopes as an ocean circulation tracer in the Southwest Atlantic

“…For Nd concentrations, a multielement REE spike enriched in 138 La, 142 Ce, 145 Nd, 149 Sm, 153 Eu, 155 Gd, 161 Dy, 167 Er, 171 Yb, and 176 Lu (Wu et al, 2020) was added to each 10 ml-sized sample. The sample-spike mixture was allowed to equilibrate for at least 24 hours and then was purified and preconcentrated through an ESI seaFast ® Automated Preconcentration System for Undiluted Seawater (Elemental Scientific Inc. or ESI, Omaha, Nebraska, USA) (Wu et al, 2020).…”

“…For Nd concentrations, a multielement REE spike enriched in 138 La, 142 Ce, 145 Nd, 149 Sm, 153 Eu, 155 Gd, 161 Dy, 167 Er, 171 Yb, and 176 Lu (Wu et al, 2020) was added to each 10 ml-sized sample. The sample-spike mixture was allowed to equilibrate for at least 24 hours and then was purified and preconcentrated through an ESI seaFast ® Automated Preconcentration System for Undiluted Seawater (Elemental Scientific Inc. or ESI, Omaha, Nebraska, USA) (Wu et al, 2020). The preconcentrated REEs were measured on a VG PlasmaQuad ExCell ® quadrupole ICP-MS, which was coupled to a CETAC Aridus TM desolvating introduction system (that minimized molecular oxide ion formation with a self-aspirated ESI Apex ST PFA micro flow nebulizer.…”

“…The preconcentrated REEs were measured on a VG PlasmaQuad ExCell ® quadrupole ICP-MS, which was coupled to a CETAC Aridus TM desolvating introduction system (that minimized molecular oxide ion formation with a self-aspirated ESI Apex ST PFA micro flow nebulizer. For quality control, we repeatedly analyze seawater samples from a GEOTRACES intercalibration station Bermuda Atlantic Time Series (BATS; 31.7°N, 64.1°W) in the North Atlantic at 20 m (n = 18) and 2000 m (n = 16) (Wu et al, 2020). For the BATS 20 and 2000 m samples, long-term external reproducibility (2σ RSD%) for Nd is 1.9% and 1.6%, respectively, using a two standard deviation filter on the data (Wu et al, 2020).…”

“…For quality control, we repeatedly analyze seawater samples from a GEOTRACES intercalibration station Bermuda Atlantic Time Series (BATS; 31.7°N, 64.1°W) in the North Atlantic at 20 m (n = 18) and 2000 m (n = 16) (Wu et al, 2020). For the BATS 20 and 2000 m samples, long-term external reproducibility (2σ RSD%) for Nd is 1.9% and 1.6%, respectively, using a two standard deviation filter on the data (Wu et al, 2020).…”