Premium
Improvement of analytical method for chlorine dual‐inlet isotope ratio mass spectrometry of organochlorines
Author(s) -
Gilevska Tetyana,
Ivdra Natalija,
Bonifacie Magali,
Richnow HansHermann
Publication year - 2015
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.7220
Subject(s) - chemistry , chlorine , isotopes of chlorine , mass spectrometry , chloride , isotope ratio mass spectrometry , gas chromatography , combustion , dissolution , analytical chemistry (journal) , isotope analysis , environmental chemistry , chromatography , organic chemistry , ecology , biology
Rationale The development of compound‐specific chlorine isotope analysis (Cl‐CSIA) is hindered by the lack of international organochlorine reference materials with isotopic compositions expressed in the δ 37 Cl notation. Thus, a reliable off‐line analytical method is needed, allowing direct comparison of the δ 37 Cl values of molecularly different organic compounds with that of ocean‐water chloride, to refer measurement results to a Standard Mean Ocean Chloride (SMOC) scale. Methods The analytical method included sealed‐tube combustion of organochlorines, precipitation and subsequent conversion of formed inorganic chlorides into methyl chloride (CH 3 Cl) for the determination of δ 37 Cl values by Dual‐Inlet Isotope Ratio Mass Spectrometry (DI‐IRMS). A sample preparation step most sensitive to the sample size – dissolution of the inorganic copper chlorides formed by combustion of organochlorines – was identified. Results Recovery of 94 ± 5% of chlorine was reached by applying determined optimal conditions for the dissolution, implying good external precision of δ 37 Cl values (–0.18 ± 0.03‰, 1σ, n = 3). Validation of the optimized method by the analysis of the produced and initial CH 3 Cl samples with known δ 37 Cl values vs SMOC resulted in a difference of 0.11 ± 0.04‰ (1σ, n = 3), confirming the external precision and accuracy of the entire method. Conclusions The efficiency of the sample preparation method for CH 3 Cl‐DI‐IRMS analysis is independent both of the chemical structure of the chlorinated compound and of the amount of chlorine in the sample. This method has the potential to be applied to a broad range of chlorinated organic compounds, e.g. reference material for the calibration of methods for Cl‐CSIA against SMOC. Copyright © 2015 John Wiley & Sons, Ltd.