Reconnaissance repertoire readied: scientists prepare for emerging dechlorane flame retardants

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  • Published: Nov 14, 2016
  • Author: Ryan De Vooght-Johnson
  • Channels: Gas Chromatography
thumbnail image: Reconnaissance repertoire readied: scientists prepare for emerging dechlorane flame retardants

Snowball effect

The grapevines are stirring. Since the turn of this millennia, rumour spoken in the less-than-hushed tones of peer-reviewed journals tells of the latest man-made chemical to taint nature: dechloranes. But like a once fist-sized snowball hurtling towards gravity, this gossip has picked up momentum and has lured many recruits to the avalanche.

The alarm was first sounded circa. 2006 when researchers working at Indiana University detected these flame retardants in the fish, water, and sediments of the Great Lakes of Illinois, Michigan, and Ohio. They reasoned that perhaps these had sloshed and spilt over from the mass-production factory upstream. But this was no isolated case.

Samples salvaged from around the world have, if anything, fuelled the concern, and it is no coincidence for these to have been washed up at the shorelines of humanity. It’s a classic tale of bioaccumulation—Sapiens eats fish that survive and dine on the polluted waters and sediment. Any impact dechloranes have on Sapiens is unknown; its study is still ongoing and the tools of the trade still being devised.

Tools of the trade

The few studies that have been conducted have reported nanograms of the stuff in as little as a 1-millilitre drop of serum, whilst other have alerted to their presence in breast milk too. These reports alone have been enough to warrant concern.

‘Human biomonitoring data are barely available for the dechloranes,’ writes Catherine Brasseur, who spearheaded the research from the University of Liège in Belgium. ‘No experimental studies have yet been reported on the toxicity or endocrine disruption potential of these analytes,’ she adds.

Writing in the Rapid Communications in Mass Spectrometry, Brasseur describes how she and her colleagues set out to devise the high-quality tools needs to obtain high-quality evidence.

Experimenting on procured sera pooled from over a thousand donors in addition to 48 individual serum samples, the Belgium-based chemists enriched the dechlorane signals from the noisy matrix using two solid-phase columns.

From here, analytes were resolved from two loop-the-loop GC columns jet-blasted with liquid nitrogen—this, they reasoned, would prevent co-elution. Next up, and to minimise the ionisation of the ever abundant yet unwanted matrix components, the nuclei of eluted analytes were coerced to capture an orbital electron using so-called electron capture negative ionisation (ECNI), where they were then mass analysed by their time-of-flight (ToF).

Selective not sensitive

Whilst past attempts to study dechloranes in serum samples have opted for scanning mass analysers—the likes of quadrupoles and magnetic sectors—Brasseur and co. broke away from this status quo. ToF, they reasoned, would enhance ion selectivity and would enable them to probe the elemental composition of ill-defined, and sometimes unknown, analytes.

Aware that halogenated and isotopic envelopes would be crucial to their analysis, their paper describes how they ramped the resolution to 5,000 FWHM (full width at half maximum). As graphically depicted, restricting the mass accuracy to just 500 m/z units enhanced the signal-to-noise ratio by at least twofold.

‘The use of full mass range TOFMS spectral data,’ the paper concludes,’ allowed us to perform elemental composition calculations, which appeared to be successful for the unambiguous identification with the specific isotope pattern recognition.’

Yet, Brasseur concedes that the high limit of detection (0.03–0.20 ng/g) could limit the application of their test.

Related Links

Rapid Commun. Mass Spectrom., 2016, 30, 2545–2554. Brasseur et al. Measurement of emerging dechloranes in human serum using modulated gas chromatography coupled to electron capture negative ionization time-of-flight mass spectrometry.

Wikipedia, Dechlorane plus.

Article by Ryan De Vooght-Johnson

The views represented in this article are solely those of the author and do not necessarily represent those of John Wiley and Sons, Ltd.

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