Premium
Compound‐specific carbon isotope analysis for mechanistic characterization of debromination of decabrominated diphenyl ether
Author(s) -
Zhu Xifen,
Zhong Yin,
Wang Heli,
Li Dan,
Deng Yirong,
Gao Shutao,
Peng Ping'an
Publication year - 2020
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.8758
Subject(s) - chemistry , isotope ratio mass spectrometry , fractionation , chromatography , isotope analysis , gas chromatography , mass spectrometry , isotope dilution , isotope , diphenyl ether , isotopes of carbon , environmental chemistry , organic chemistry , total organic carbon , ecology , physics , quantum mechanics , biology
Rationale Decabrominated diphenyl ether (BDE‐209) is a notorious persistent organic pollutant widely found in the environment. Developing a compound‐specific isotope analysis (CSIA) method is much needed in order to trace its transport and degradation processes and to evaluate the effectiveness of the remediation of BDE‐209 in the environment. However, the conventional CSIA method, i.e. gas chromatography (GC) combustion isotope ratio mass spectrometry, is not appropriate for BDE‐209 because of its high thermal instability and incomplete combustion. Methods We developed a high‐performance liquid chromatography (HPLC) method for the separation and purification of BDE‐209 that prevents its thermal reactivity as occurred in prior GC‐based methods. The δ 13 C value of the purified BDE‐209 was determined using offline elemental analyzer isotope ratio mass spectrometry (EA/IRMS). This two‐step method was applied to determine the δ 13 C values of BDE‐209 in two commercial samples and to characterize carbon isotope fractionation associated with the debromination of BDE‐209 via nanoscale zero‐valent iron. Results The mean values of daily δ 13 C analyses of six replicates of a BDE‐209 standard varied from −27.66‰ to −27.92‰, with a standard deviation ranging from 0.07‰ to 0.16‰, indicating a good reproducibility of EA/IRMS. The EA/IRMS analysis of the purified BDE‐209 standard indicated no obvious isotope fractionation during the sample purification. The impurity content in commercial BDE‐209 samples may contribute additional variation of the δ 13 C values of BDE‐209. The δ 13 C values of BDE‐209 gradually changed from −27.47 ± 0.37‰ to −24.59 ± 0.19‰ when 74% of the BDE‐209 standard was degraded within 36 h. The estimated carbon isotope enrichment factor was −1.72 ± 0.18‰. Conclusions The two‐step method based on HPLC and EA/IRMS avoids the thermal instability of BDE‐209 in the traditional CSIA method. It offers a novel approach for elucidating the degradation mechanisms of BDE‐209 in the environment and for source identification in contaminated sites.