Determination of Se and Te in coal at ultra-trace levels by ICP-MS after microwave-induced combustion

Filipe S. Rondan, Alessandra S. Henn, Paola A. Mello, Magali Perez, Liam A. Bullock, John Parnell, Joerg Feldmann, Erico M. M. Flores, Marcia F. Mesko* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

A method for ultra-trace determination of Se and Te in coal by inductively coupled plasma mass spectrometry (ICP-MS) was developed. Samples (up to 500 mg) were prepared by microwave-induced combustion (MIC) in a closed system pressurized with 20 bar of oxygen. Inorganic acids or their mixtures were evaluated as absorbing solution. Using HNO 3 + HCl (1 + 1), results obtained for Se and Te after sample preparation by MIC agreed with those obtained by reference methods, microwave-assisted wet digestion (MAWD) using concentrated HNO 3 and HF, and solid sampling electrothermal vaporization inductively coupled plasma mass spectrometry (SS-ETV-ICP-MS), and also with a certified reference material of coal (NIST 1632c) for Se. Very low limits of quantification (LOQ) were obtained: 0.002 and 0.007 mg kg -1 for Se and Te, respectively. Major elements were determined in final solutions obtained by MAWD and MIC, and their concentration in solutions of MIC was negligible (<10 μg L -1 ), minimizing the risk of interference in ICP-MS analysis. The proposed method was applied to samples of coal from the United Kingdom, with a wide range of inorganic composition (from 3 to 41% ash content), showing its robustness and feasibility for routine analysis. Se concentration ranged from 0.291 to 11.5 mg kg -1 , and Te was mainly found at ultra-trace levels (<0.007 to 0.11 mg kg -1 ). The proposed method presents several advantages over the reference methods, such as the use of a higher sample mass, low LOQs and, an important aspect, no need of using HF.

Original languageEnglish
Pages (from-to)998-1004
Number of pages7
JournalJournal of Analytical Atomic Spectrometry
Volume34
Issue number5
Early online date28 Feb 2019
DOIs
Publication statusPublished - 1 May 2019

Keywords

  • SAMPLE PREPARATION
  • TOXIC ELEMENTS
  • DIGESTION
  • FEASIBILITY
  • IMPURITIES
  • STRATEGIES
  • TELLURIUM
  • HALOGENS
  • SELENIUM
  • SULFUR

ASJC Scopus subject areas

  • Analytical Chemistry
  • Spectroscopy

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