Premium
Simplified sample preparation procedure for measuring isotope‐enriched methylmercury by gas chromatography and inductively coupled plasma mass spectrometry
Author(s) -
Avramescu MaryLuyza,
Zhu Joy,
Yumvihoze Emmanuel,
Hintelmann Holger,
Fortin Danielle,
Lean David R.S.
Publication year - 2010
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.158
Subject(s) - chemistry , chromatography , derivatization , inductively coupled plasma mass spectrometry , mercury (programming language) , sample preparation , gas chromatography , mass spectrometry , analyte , certified reference materials , detection limit , distillation , gas chromatography–mass spectrometry , computer science , programming language
Many procedures have been developed to measure the concentration of monomethylmercury (MeHg) from different sample matrices, and the use of stable isotopes of mercury now provides opportunities to determine its formation and degradation rates. Here, a modified procedure for measuring mercury isotopes in sediment samples that uses acid leaching‐ion exchange‐thiosulfate extraction (TSE) to isolate and purify the methylated mercury from the matrix is proposed. The latter is followed by aqueous‐phase ethylation, purge and trap on Tenax, gas chromatography separation of ethylated mercury compounds, and inductively coupled plasma mass spectrometry detection. The new TSE procedure bridges together two well‐known methods, the acid‐leaching and distillation‐derivatization procedures, offering the advantages of artifact‐free formation of the first, and low detection limits and the possibility of quantification of individual isotopes of mercury of the second. The modified procedure retains the derivatization, purge and trap, and gas chromatography and inductively coupled plasma mass spectrometry (GC‐ICP‐MS) detection steps from the distillation‐derivatization procedure, and eliminates the distillation step, which is not only laborious but also expensive, due to the high cost of installation and time‐consuming cleaning process. Major advantages of the TSE procedure proposed include the extraction and analysis of a large number of samples in a short time, excellent analyte recoveries, and the lack of artifact formation. Sediment certified reference materials (CRMs), BCR 580 and IAEA 405, were used to test the TSE procedure accuracy. Recoveries between 94 to 106% and 95 to 96% were obtained for CRMs and spiked samples (Milli‐Q® water), respectively. Comparisons among thiosulfate extraction, distillation, and acid‐leaching procedures have shown good agreement of methylmercury values. Environ. Toxicol. Chem. 2010;29:1256–1262. © 2010 SETAC