The strength in numbers: comprehensive characterization of house dust using complementary mass spectrometric techniques

Abstract

Untargeted analysis of a composite house dust sample has been performed as part of a collaborative effort to evaluate the progress in the field of suspect and nontarget screening and build an extensive database of organic indoor environment contaminants. Twenty-one participants reported results that were curated by the organizers of the collaborative trial. In total, nearly 2350 compounds were identified (18%) or tentatively identified (25% at confidence level 2 and 58% at confidence level 3), making the collaborative trial a success. However, a relatively small share (37%) of all compounds were reported by more than one participant, which shows that there is plenty of room for improvement in the field of suspect and nontarget screening. An even a smaller share (5%) of the total number of compounds were detected using both liquid chromatography–mass spectrometry (LC-MS) and gas chromatography–mass spectrometry (GC-MS). Thus, the two MS techniques are highly complementary. Most of the compounds were detected using LC with electrospray ionization (ESI) MS and comprehensive 2D GC (GC×GC) with atmospheric pressure chemical ionization (APCI) and electron ionization (EI), respectively. Collectively, the three techniques accounted for more than 75% of the reported compounds. Glycols, pharmaceuticals, pesticides, and various biogenic compounds dominated among the compounds reported by LC-MS participants, while hydrocarbons, hydrocarbon derivatives, and chlorinated paraffins and chlorinated biphenyls were primarily reported by GC-MS participants. Plastics additives, flavor and fragrances, and personal care products were reported by both LC-MS and GC-MS participants. It was concluded that the use of multiple analytical techniques was required for a comprehensive characterization of house dust contaminants. Further, several recommendations are given for improved suspect and nontarget screening of house dust and other indoor environment samples, including the use of open-source data processing tools. One of the tools allowed provisional identification of almost 500 compounds that had not been reported by participants. Electronic supplementary material The online version of this article (10.1007/s00216-019-01615-6) contains supplementary material, which is available to authorized users.

Transthyretin-Binding Activity of Complex Mixtures Representing the Composition of Thyroid-Hormone Disrupting Contaminants in House Dust and Human Serum

“…Because all 12 contaminants were inactive as TRb antagonists on an individual basis, these results suggest either a synergistic mechanism or the presence of unknown TRb antagonistic contaminants in house dust co-occurring with the 12 flame retardants. Previous nontargeted screening studies (Rager et al 2016;Rostkowski et al 2019) have confirmed that house dust contains thousands of chemicals of which the identity is unknown, let alone their TH disrupting capacity. Still, the different patterns in major contributors to the TTR-binding potencies in the mixtures reflecting known TTRbinding compounds in human blood and house dust indicate that dust is not the only route of human exposure to TTR-binding compounds.…”

Measured concentrations of consumer product chemicals in California house dust: Implications for sources, exposure, and toxicity potential

“…Rager et al applied suspect screening and non‐target methods to 50 household dust samples collected in the US from 2005 to 2006 using LC‐TOF/MS. A comparative study of a non‐target analysis was conducted in a composite house dust sample as part of a collaborative effort using LC‐MS and GC‐MS . The methods used in the four studies are useful for identifying previously unknown and even unexpected chemicals in dust, but none of them presented concentrations that were confirmed and quantified by standards.…”

High resolution mass spectrometry-based non-target screening can support regulatory environmental monitoring and chemicals management

“…Bench-top instruments are becoming available in many regional and national environmental monitoring laboratories, and the relevant competences in regulatory authorities and the availability of analytical experts have increased. Collaborative trials on water [11] and dust [12] have been started by the NORMAN network and have subsequently also been performed by the US EPA [13] and in other national networks (e.g. German Chemical Society; Fig.…”