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A rapid and high‐precision method for sulfur isotope δ 34 S determination with a multiple‐collector inductively coupled plasma mass spectrometer: matrix effect correction and applications for water samples without chemical purification
Author(s) -
Lin AnJun,
Yang Tao,
Jiang ShaoYong
Publication year - 2014
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.6838
Subject(s) - seawater , chemistry , inductively coupled plasma mass spectrometry , analytical chemistry (journal) , ammonium sulfate , matrix (chemical analysis) , sulfur , mass spectrometry , sulfate , isotope , inductively coupled plasma , standard solution , standard addition , chromatography , detection limit , plasma , oceanography , physics , organic chemistry , quantum mechanics , geology
RATIONALE Previous studies have indicated that prior chemical purification of samples, although complex and time‐consuming, is essential in obtaining precise and accurate results for sulfur isotope ratios using multiple‐collector inductively coupled plasma mass spectrometry (MC‐ICP‐MS). In this study, we introduce a new, rapid and precise MC‐ICP‐MS method for sulfur isotope determination from water samples without chemical purification. METHODS The analytical work was performed on an MC‐ICP‐MS instrument with medium mass resolution (m/Δm ~ 3000). Standard‐sample bracketing (SSB) was used to correct samples throughout the analytical sessions. Reference materials included an Alfa‐S (ammonium sulfate) standard solution, ammonium sulfate provided by the lab of the authors and fresh seawater from the South China Sea. A range of matrix‐matched Alfa‐S standard solutions and ammonium sulfate solutions was used to investigate the matrix (salinity) effect (matrix was added in the form of NaCl). A seawater sample was used to confirm the reliability of the method. RESULTS Using matrix‐matched (salinity‐matched) Alfa‐S as the working standard, the measured δ 34 S value of AS (−6.73 ± 0.09‰) was consistent with the reference value (−6.78 ± 0.07‰) within the uncertainty, suggesting that this method could be recommended for the measurement of water samples without prior chemical purification. The δ 34 S value determination for the unpurified seawater also yielded excellent results (21.03 ± 0.18‰) that are consistent with the reference value (20.99‰), thus confirming the feasibility of the technique. CONCLUSIONS The data and the results indicate that it is feasible to use MC‐ICP‐MS and matrix‐matched working standards to measure the sulfur isotopic compositions of water samples directly without chemical purification. In comparison with the existing MC‐ICP‐MS techniques, the new method is better for directly measuring δ 34 S values in water samples with complex matrices; therefore, it can significantly accelerate analytical turnover. Copyright © 2014 John Wiley & Sons, Ltd.