Femtogram detection of perfluorocarbon tracers using capillary gas chromatography-electron-capture negative ion chemical ionisation mass spectrometry

doi:10.1016/S0021-9673(01)84513-1

Journal of Chromatography A

Volume 445, 1988, Pages 119-128

https://doi.org/10.1016/S0021-9673(01)84513-1 Get rights and content

Abstract

An ultrasensitive and selective method has been developed for the detection of a range of perfluorocarbon tracers suitable for long-range atmospheric studies. Following direct injection onto a capillary column the perfluorocarbons are separated and detected using mass spectrometry with electron-capture negative ion chemical ionisation (ECNICI-MS) with methane as reagent gas and selected-ion monitoring. All nine perfluorocarbons tested underwent non-dissociative resonance electron capture to form the molecular anion which was the base peak in all cases. Using this technique, detection limits (signal-to-noise ratio of 2:1) of 3 and 2 fg were obtained for perfluoromethylcyclohexane and perfluoro-1,3-dimethylcyclohexane respectively. The corresponding detection limits using a conventional electron-capture detector were 8 and 9 fg respectively. In addition to increased sensitivity, the ECNICI-MS technique allows temperature programming for the simultaneous analysis of a range of perfluorocarbons and has superior selectivity being less prone to coeluting interference. Furthermore the method is potentially one to two orders of magnitude more sensitive than the current gas chromatography-MS methods using ¹³C²H₄ tracers.

References (18)

B. Lamb et al.
Atmos. Environ.
(1986)
J.E. Lovelock et al.
Atmos. Environ.
(1982)
M. Alei et al.
Atmos. Environ.
(1987)
P.G. Simmonds et al.
J. Chromatogr.
(1976)
S. Shang-Zhi et al.
J. Chromatogr.
(1984)
P. Begley et al.
J. Chromatogr.
(1986)
M. Oehme et al.
J. Chromatogr.
(1983)
J.R. Ledwell et al.
Nature (London)
(1986)
G.J. Ferber et al.
EPA Report
(1981)

There are more references available in the full text version of this article.

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Unfortunately the atmospheric background concentrations of several perfluorocarbon tracers (see Table 1) are believed to have increased to about 10 ppq due to emissions from various industrial applications, and their release in several major tracer experiments (Draxler et al., 1991, Straume et al., 1998; Nordop et al., 1998; Kim et al., 2002), (see Table 1). Assuming we can accurately determine the current atmospheric background concentration of these specific c-PFCs, we could still design experiments which release sufficient amounts of tracer to overpower this non-zero background, thereby providing a substantial enhancement which can be measured with high precision (Begley et al., 1988). Based on the release of a novel perfluorocarbon tracer (i.e. with zero background concentration) and a 1L sample volume it should be possible to determine a tracer atmospheric mixing ratio of 10 ppq with high precision, assuming quantitative trapping and detection of the tracer.
Atmospheric tracers are effective tools for characterizing dispersion and for testing computational models of atmospheric transport. Atmospheric trace gas measurements are now used widely to infer geographical surface flux distributions. However, robust flux estimates critically rely on well-validated knowledge of atmospheric chemistry, loss processes and transport, without which we are not fully realizing the potential of atmospheric measurements collected on the ground, or from aircraft and satellites. This challenge has taken on renewed importance in the shadow of the Paris Agreement that will likely take advantage of atmospheric trace gas measurements to help improve national and global greenhouse gas emission budgets. We describe a wide range of existing and new potential atmospheric tracers for improving our understanding of atmospheric dispersion. We consider the investigation of atmospheric transport over two scales: (1) short-to-medium length scale (on the order of 1–1000 km) to improve our understanding of convection and boundary layer transport processes, and (2) hemisphere-to-global length scale (on the order of 1000–10,000 km), where large-scale mixing, cross hemisphere transport and stratosphere-troposphere exchange are important. Although we note the possibility of using “tracers of opportunity,” our primary focus is on deliberate-release tracers, and we explore the use of cyclic perfluorocarbons, hydrofluorocarbons, hydrochlorofluorocarbons, hydrofluoroethers and novel tracers of deuterium-substituted halocarbons. We examine how we might exploit existing instrumentation already deployed at remote global monitoring sites as well as requirements for new instrumentation. To guide the discussion, we provide example scenarios for how experiments might be set up, covering regional to global spatial scales for the evaluation and improvement of atmospheric transport models. However, we stress that appropriate three-dimensional modelling studies and preliminary experiments would need to be carried out to determine the specific details of any real-world experiment.
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A systematic mass spectrometry study of an industrially prolific class of polyfluorinated compounds known as telomers was conducted. The study specifically focused upon polyfluorinated alcohols along with corresponding saturated and α,β-unsaturated fluoroacids. Within each class differing fluoroalkyl chain length homologues were investigated, using negative and positive chemical ionization mass spectrometry (NCI and PCI). In the case of the fluoroalcohols, NCI resulted in the production of more elaborate spectra than the other classes. Moreover, it showed the interesting production of HF₂⁻ and the complex of this species, along with F⁻, with the parent molecule. These complexes resulted in the formation of the novel H₂F₃⁻ ion. Results show that there is significant intra-molecular hydrogen bonding that occurs for these compounds, which influences the molecules fragmentation. This bonding will also influence the fate and disposition through environmental processes (e.g., V_P, k_OH, K_OW, K_OA) which are affected by molecular geometry. Furthermore, there is an increased accumulation and persistence potential for the molecule as a function of the fluorocarbon chain length. We have shown that in conjunction with the use of mass spectroscopy the engertics of environmental processes for polyfluorinated materials can be established.
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The background atmospheric mixing ratios for a range of cyclic perfluorocarbons (cyclic-PFCs), widely used in atmospheric dispersion studies, have been measured by gas chromatography-mass spectrometry in negative ion-chemical ionization mode. Background concentrations range from <1 fl l⁻¹ to >10 fl l⁻¹, where femtolitre is expressed as parts in 10¹⁵ (ppqv). Because of their very long atmospheric lifetimes (>3000 yr) the present day concentrations represent the accumulated emissions from all sources, although significant commercial production did not commence until the 1960s. Cyclic-PFCs are potent greenhouse gases; however, their atmospheric concentrations are currently so low as to make an insignificant contribution to global warming.
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Les perfluorocarbures (PFC) sont des molécules dérivées d'hydrocarbures linéaires ou cycliques dans lesquelles les atomes d'hydrogène ont été remplacés par des atomes de fluor. Ces molécules présentent un certain nombre de propriétés remarquables parmi lesquelles une grande inertie chimique et biologique et une grande capacité à dissoudre les gaz. Ces propriétés font qu'ils sont en passe d'être utilisés en médecine comme transporteurs d'oxygène (sang artificiel) sous forme d'émulsions. Ces dernières années, la rumeur a laissé penser qu'ils seraient utilisés par certains athlètes pour augmenter leurs performances aérobies. Absents dans les urines, les PFC peuvent cependant être aisément décelés dans le sang ou l'air expiré, ce qui devrait dissuader les athlètes de leur utilisation.
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A new contrast agent (Sonazoid^TM; NC100100) for ultrasound imaging has been developed. It is an aqueous suspension of lipid stabilised perfluorobutane (PFB) gas microbubbles. An automatic headspace capillary gas-chromatographic mass spectrometric method using electron impact ionisation was developed for analysis of Sonazoid^TM PFB in rat blood. The calibration standards were gaseous PFB dissolved in ethanol in the range of 0.5–5000 ng PFB. Fluorotrichloromethane (CFC 11) was used as an internal standard of the method and the MS detector was set to single ion monitoring of the base fragment ions of PFB (m/z 69 and 119) and CFC 11 (m/z 101). The calibration graph, made by plotting the peak area ratios of PFB (m/z 69) to CFC 11(m/z 101) against the amount of PFB, was fitted to a second-order polynomial equation with weighting 1/y² and found to be reproducible. The limit of quantification of the method was set to 0.4 ng PFB. The between-day variation of the method was below 9.2% relative standard deviation (RSD) and the within-day variation of the method was below 7.6% RSD. The accuracy of the method, as compared to Coulter counter, was estimated by determination of PFB in samples where Sonazoid^TM was added to saline and found to range from 91.5% to 105.2%. PFB, added as Sonazoid^TM, was found to be stable for at least 7 months in rat blood samples when stored at −20°C.

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Femtogram detection of perfluorocarbon tracers using capillary gas chromatography-electron-capture negative ion chemical ionisation mass spectrometry

Abstract

Atmos. Environ.

Atmos. Environ.

Atmos. Environ.

J. Chromatogr.

J. Chromatogr.

J. Chromatogr.

J. Chromatogr.

Nature (London)

EPA Report