Title: Solid matrix transformation and tracer addition using molten ammonium bifluoride salt as a sample preparation method for laser ablation inductively coupled plasma mass spectrometry

Abstract

Solid sampling and analysis methods, such as laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), are challenged by matrix effects and calibration difficulties. Matrix-matched standards for external calibration are seldom available and it is difficult to distribute spikes evenly into a solid matrix as internal standards. While isotopic ratios of the same element can be measured to high precision, matrix-dependent effects in the sampling and analysis process frustrate accurate quantification and elemental ratio determinations. Here we introduce a potentially general solid matrix transformation approach entailing chemical reactions in molten ammonium bifluoride (ABF) salt that enables the introduction of spikes as tracers or internal standards. Proof of principle experiments show that the decomposition of uranium ore in sealed PFA fluoropolymer vials at 230 °C yields, after cooling, new solids suitable for direct solid sampling by LA. When spikes are included in the molten salt reaction, subsequent LA-ICP-MS sampling at several spots indicate that the spikes are evenly distributed, and that U-235 tracer dramatically improves reproducibility in U-238 analysis. Precisions improved from 17% relative standard deviation for U-238 signals to 0.1% for the ratio of sample U-238 to spiked U-235, a factor of over two orders of magnitude. These results introduce themore » concept of solid matrix transformation (SMT) using ABF, and provide proof of principle for a new method of incorporating internal standards into a solid for LA-ICP-MS. This new approach, SMT-LA-ICP-MS, provides opportunities to improve calibration and quantification in solids based analysis. Finally, looking forward, tracer addition to transformed solids opens up LA-based methods to analytical methodologies such as standard addition, isotope dilution, preparation of matrix-matched solid standards, external calibration, and monitoring instrument drift against external calibration standard« less

Authors:

Grate, Jay W.  ^[1];

• Search DOE PAGES for author "Grate, Jay W."
• Search DOE PAGES for ORCID "0000-0002-2163-8383"

Gonzalez, Jhanis J. ^[2]; O'Hara, Matthew J.  ^[1];

• Search DOE PAGES for author "O'Hara, Matthew J."
• Search DOE PAGES for ORCID "0000-0003-3982-5897"

Kellogg, Cynthia M. ^[1]; Morrison, Samuel S. ^[1]; Koppenaal, David W. ^[1]; Chan, George C. -Y. ^[1]; Mao, Xianglei ^[1]; Zorba, Vassilia ^[3]; Russo, Richard E. ^[2]

---

+ Show Author Affiliations

1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Applied Spectra, Fremont, CA (United States)
3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Publication Date:

Thu Jun 22 00:00:00 EDT 2017

Research Org.:

Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1532263

Grant/Contract Number:  

AC02-05CH11231

Resource Type:

Accepted Manuscript

Journal Name:

Analyst

Additional Journal Information:

Journal Volume: 142; Journal Issue: 18; Journal ID: ISSN 0003-2654

Publisher:

Royal Society of Chemistry

Country of Publication:

United States

Language:

English

Subject:

47 OTHER INSTRUMENTATION