Development of methodology for the determination of carbon isotope ratios using gas chromatography/combustion/isotope ratio mass spectrometry and applications in the biodegradation of phenolic brominated flame retardants and their degradation products

Abstract

RATIONALE:Compound-specific stable carbon isotope analysis of phenolic brominated flame retardants (BFRs) and bisphenol A (BPA) has proven informative to discriminate their source and fate apportionment in the environment. However, because these compounds contain highly polar functional groups and exist as complex mixtures in environment matrices, derivatization is a necessary step, which adds additional non-analyte carbon atoms for analyses and may alter the original stable carbon isotope ratio. It is, therefore, imperative to gain an insight into the relationship between the δ 13 C values of the BFRs and BPA derivatives and those of underivatized BFRs and BPA. METHODS: The δ 13 C values of BFRs and BPA N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) derivatives were measured by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). The δ 13 C values of the BSTFA reagent and the standard underivatized BFRs and BPA were determined using elemental analyzer/isotope ratio mass spectrometry (EA/IRMS). The experimentally obtained δ 13 C values for BFRs and BPA derivatives were then compared with the theoretically calculated values. RESULTS: The derivatization process introduces no isotopic fractionation for BFRs and BPA (the average difference between the theoretically calculated and experimentally obtained δ 13 C values was 0.06 ± 0.15‰, within the precision limits of the GC/C/IRMS measurements). Therefore, the δ 13 C values for the original underivatized BFRs and BPA were computed through a mass balance equation. CONCLUSIONS: This work offers a novel tool to research the biotic or abiotic transformation processes of BFRs and BPA in the environment and will offer a perspective for the identification of the environmental source and fate of these organic compounds. Copyright © 2014 John Wiley & Sons, Ltd.Brominated flame retardants (BFRs) are a group of organic compounds extensively incorporated into a multitude of products such as building materials, electrical and electronic products, textiles and foams to protect materials against ignition. [1] Among these BFRs, more than one-third are phenolic BFRs, including tetrabromobisphenol A (TBBPA), 2,4,6-tribromophenol (TBP), 2,4-dibromophenol (2,4-DBP) and 2,6-dibromophenol (2,6-DBP), [2] with a total global market that increased from 130 000 tons in 2002 to over 170 000 tons in 2004. [3] Bisphenol A (BPA) has also been widely used as an intermediate in the synthesis of polycarbonate plastics, epoxy resins and flame retardants. [4] However, during the production, use or dismantling of these products, a proportion of the BFRs can be released into the environment. Therefore, BFRs and BPA are of great concern because of their ubiquitous presence and recalcitrant persistence in various environmental matrices, including biota, and their potential adverse effects on wildlife and humans. [5][6][7][8][9] The biodegradation or photochemical transformation of these substances occurs once they are released into the environment. Among the various environmental t...

Development and Application of a Purification Method for the Determination of Three EDCs Isotopes in Sediments and Water

“…The δ 13 C values of OP, NP, and BPA derivatives were −26.80‰, −29.04‰, and −28.91‰, respectively, with the standard deviation (SD) ranging from 0.30‰ to 0.47‰ (Table 1). Compared with the results obtained using hydroxy derivatization, the SD in this study is slightly larger than that in previous studies (ranging from 0.16‰ to 0.24‰) [24]. However, the values in our results are smaller than those in other CSIA results (ranging from 0.05‰ to 0.78‰) [28], and the relative standard deviation (RSD) is still less than 2%, indicating that the results are still reliable.…”

“…The hydrogen atoms of the OH group were replaced by the TMS group. It is proven that the derivatization process does not cause isotopic fractionation [24]. Due to the introduction of new carbon atoms, the δ 13 C value determined using GC-C-IRMS was the isotope value of the derivative, and the isotope values of the original compound could be calculated using Equation (2).…”

“…Xiong et al found that no carbon isotopic fractionation was observed during the biodegradation of BPA. A microcosmic study [24] indicated that it is difficult to use carbon isotopes to determine whether BPA is reactive. CSIA has become a widely used method to identify the source and degradation way of organic compounds [17,18,20,21,31].…”

“…In this case, CSIA can be used to trace the source of organic compounds. Xiong et al found that no significant carbon isotopic fractionation was observed during the biodegradation of BPA in a microcosmic experiment and deemed CSIA suitable for identifying the environmental source of BPA [24]. CSIA was also used to trace the sources of polychlorinated biphenyls (PCBs) [15].…”

Co-metabolic biodegradation of 4-bromophenol in a mixture of pollutants system by Arthrobacter chlorophenolicus A6

“…Besides, the combustion of leaded petrol produces a considerable quantity of bromophenol (Sahoo et al 2013). The annual global production of bromophenol ame retardant (BFRs) has been raised from 0.13 million tons in 2002 to over 0.2 million tons in 2013 (Xiong et al 2015).The world wide annual production of bromophenol isover 23,000 tons (Liang et al 2017). The concentration of bromophenol rises to 187 mgl − 1 in the e uent of photographic industrial wastewater (Sahoo et al 2014a).…”