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Bowden, Derek; Clegg, Simon L.; Brimblecombe, Peter

doi:10.1023/a:1005899813756

Cited by 39 publications

(19 citation statements)

References 41 publications

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“…The source of TCA in precipitation is most likely of atmospheric origin because the low Henry's law constant would preclude its volatilization from surface water or soil (19,20). The atmospheric degradation of tetrachloroethene and possibly 1,1,1-trichloroethane may make a significant contribution to the TCA concentrations in precipitation, but additional sources may also exist (16,19,21).…”

Section: Introductionmentioning

confidence: 99%

“…Trace amounts of CDFA have been detected in air samples collected on alkalized cylindrical denuders (1); however, quantitative data were not reported. Because of the low Henry's law constant for CDFA (4 × 10 -5 kg atm mol -1 at 298.15 K) (20), we hypothesized that CDFA would be efficiently scavenged from air by cloudwater and ultimately deposited in precipitation. The objectives of this study were to quantitatively determine and confirm the presence of CDFA in precipitation, to examine its phytotoxicity and environmental persistence, and to discuss the possible atmospheric sources.…”

Section: Introductionmentioning

confidence: 99%

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Detection of Chlorodifluoroacetic Acid in Precipitation: A Possible Product of Fluorocarbon Degradation

Martin

Franklin

Hanson

et al. 1999

Environ. Sci. Technol.

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Chlorodifluoroacetic acid (CDFA) was detected in rain and snow samples from various regions of Canada. Routine quantitative analysis was performed using an in-situ derivatization technique that allowed for the determination of CDFA by GC-MS of the anilide derivative. Validation of environmental CDFA was provided by strong anionic exchange chromatography and detection by 19 F NMR. CDFA concentrations ranged from <7.1 to 170 ng L -1 among all samples analyzed. Monthly volume-weighted CDFA concentrations in rain event samples showed a seasonal trend between June and November 1998, peaking in late summer and decreasing in the fall for Guelph and Toronto sites. Preliminary toxicity tests with the aquatic macrophytes Myriophyllum sibiricum and Myriophyllum spicatum suggest that CDFA does not represent a risk of acute toxicity to these aquatic macrophytes at current environmental concentrations. A degradation study suggests that CDFA is recalcitrant to biotic and abiotic degradation relative to dichloroacetic acid (DCA) and may accumulate in the aquatic environment. On the basis of existing experimental data, we postulate that CDFA is a degradation product of CFC-113 and, to a lesser extent, HCFC-142b. If CFC-113 is a source, its ozone depletion potential may be lower than previously assumed. Further work is required to identify alternative atmospheric and terrestrial sources of CDFA.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Detection of Chlorodifluoroacetic Acid in Precipitation: A Possible Product of Fluorocarbon Degradation

Martin

Franklin

Hanson

et al. 1999

Environ. Sci. Technol.

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“…The atmospheric origin of DFA found in the rainwater has to remain an open question. As significant volatilization of TFA and DFA from water bodies can be excluded due to their physicochemical characteristics [23], the possible options are atmospheric oxidation of some difluoromethyl compounds or reductive defluorination of TFA that has not been observed in the atmosphere so far.…”

Section: Resultsmentioning

confidence: 99%

Evidence for the Formation of Difluoroacetic Acid in Chlorofluorocarbon-Contaminated Ground Water

2019

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The concentrations of difluoroacetic acid (DFA) and trifluoroacetic acid (TFA) in rainwater and surface water from Berlin, Germany resembled those reported for similar urban areas, and the TFA/DFA ratio in rainwater of 10:1 was in accordance with the literature. In contrast, nearby ground water historically contaminated with 1,1,2-trichloro-1,2,2-trifluoroethane (R113) displayed a TFA/DFA ratio of 1:3. This observation is discussed versus the inventory of microbial degradation products present in this ground water along with the parent R113 itself. A microbial transformation of chlorotrifluoroethylene (R1113) to DFA so far has not been reported for environmental media, and is suggested based on well-established mammalian metabolic pathways.

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“…When the donor phase is an acidic aqueous solution of pH much lower than the p K a of HA and the acceptor phase is a basic aqueous solution, the acidic analyte exists in the neutral form HA in the donor phase and the HS, while dominantly in the ionized form A − in the acceptor phase. Then the distribution coefficient D d becomes equal to Henry's law constant k H ≡ [HA] h /[HA] d , and the distribution coefficient D a can be expressed as :

D_{normala} = \frac{D_{d}}{(K_{normala} (/) {[H^{‫}]}_{normala}) ‫ 1}

…”

Section: Resultsmentioning

confidence: 99%

Headspace‐single drop microextraction with a commercial capillary electrophoresis instrument

et al. 2012

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Automated coupling of headspace-single drop microextraction (HS-SDME) and CE has been demonstrated using a commercial CE instrument. When a drop hanging at the inlet tip of a capillary for CE is used as the acceptor phase, HS-SDME becomes a simple but powerful sample pretreatment technique for CE before injection to facilitate sample cleanup and enrichment. By combining HS-SDME with an on-line sample preconcentration technique, large volume sample stacking using an electroosmotic flow pump, the sensitivity can be improved further. The overall enrichment factors for phenolic compounds were from 1900 to 3400. HS-SDME large volume sample stacking using an electroosmotic flow pump was successfully applied to a red wine sample to obtain an LOD of 4 nM (0.8 ppb) for 2,4,6-trichlorophenol which is a precursor for 2,4,6-trichloroanisole causing the foul odor in wine called cork taint.

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Untitled

Cited by 39 publications

References 41 publications

Detection of Chlorodifluoroacetic Acid in Precipitation: A Possible Product of Fluorocarbon Degradation

Detection of Chlorodifluoroacetic Acid in Precipitation: A Possible Product of Fluorocarbon Degradation

Evidence for the Formation of Difluoroacetic Acid in Chlorofluorocarbon-Contaminated Ground Water

Headspace‐single drop microextraction with a commercial capillary electrophoresis instrument

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