The current study focuses on the analysis of SRM 2585 extracts that were distributed as part of ENTACT. It further introduces a separate recovery experiment, using SRM 2585, designed to shed light on factors that affect analyte loss during extraction, cleanup, instrumental analysis, and data processing. Many compounds have been measured and reported in SRM 2585 to date; cross-referencing these compounds against those detected via NTA provides a unique means with which to critically evaluate NTA performance in a real-world context. The recovery experiment described herein further informs factors (e.g., matrix, extraction procedures) that influence compound identification using NTA. Finally, by analyzing the same mixture of compounds at different concentrations and in the presence and absence of dust matrix, the performance of NTA is evaluated here from a quantitative perspective, rather than a typical qualitative perspective. This dataset is associated with the following publication: Newton, S., J. Sobus, E. Ulrich, R. Singh, A. Chao, J. McCord, S. Laughlin-Toth, and M. Strynar. Examining NTA Performance and Potential Using Fortified and Reference House Dust as Part of EPA's Non-Targeted Analysis Collaborative Trial (ENTACT). Analytical and Bioanalytical Chemistry. Springer, New York, NY, USA, 412: 4221–4233, (2020).

We propose to develop a new highly sensitive instrument to confirm the existence of the so-called nano-dust particles, characterize their impact parameters, and measure their chemical composition. Simultaneous theoretical studies will be used to derive the expected  mass and velocity ranges of these putative particles to formulate science and measurement requirements for the future deployment of  the proposed Nano-Dust Analyzer (NDA) 

Early dust instruments onboard Pioneer 8 and 9 and Helios spacecraft detected a flow of submicron sized dust particles coming from the direction of the Sun. These particles originate in the inner solar system from mutual collisions among meteoroids and move on  hyperbolic orbits that leave the Solar System under the prevailing radiation pressure force. Later dust instruments with higher  sensitivity had to avoid looking toward the Sun because of interference from the solar wind and UV radiation and thus contributed  little to the characterization of the dust stream. The one exception is the Ulysses dust detector that observed escaping dust particles  high above the solar poles, which confirm the suspicion that charged nanometer sized dust grains are carried to high heliographic  latitudes by electromagnetic interactions with the Interplanetary Magnetic Field (IMF). Recently, the STEREO WAVES instruments  recorded a large number of intense electric field signals, which were interpreted as impacts from nanometer sized particles striking the  spacecraft with velocities of about the solar wind speed. This high flux and strong spatial and/or temporal variations of nanometer  sized dust grains at low latitude appears to be uncorrelated with the solar wind properties. This is a mystery as it would require that  the total collisional meteoroid debris inside 1 AU is cast in nanometer sized fragments. The observed fluxes of inner-source pickup ions  also point to the existence of a much enhanced dust population in the nanometer size range. 

This new heliospherical phenomenon of nano-dust streams may have consequences throughout the planetary system, but as of yet no dust instrument exists that could be used to shed light on their properties.  We propose to develop a dust analyzer capable to detect and  analyze these mysterious dust particles coming from the solar direction and to embark upon complementary theoretical studies to  understand their characteristics. The instrument is based on the Cassini Dust Analyzer (CDA) that has analyzed the composition of  nanometer sized dust particles emanating from the Jovian and Saturnian systems but could not be pointed towards the Sun. By  applying technologies implemented in solar wind instruments and coronagraphs a highly sensitive dust analyzer will be developed and  tested in the laboratory. The dust analyzer shall be able to characterize impact properties (impact charge and energy distribution of  ions from which mass and speed of the impacting grains may be derived) and chemical composition of individual nanometer sized  particles while exposed to solar wind and UV radiation. The measurements will enable us to identify the source of the dust by  comparing their elemental composition with that of larger micrometeoroid particles of cometary and asteroid origin and will reveal  interaction of nano-dust with the interplanetary medium by investigating the relation of the dust flux with solar wind and IMF  properties. 

Complementary theoretically studies will be performed to understand the characteristics of nano-dust particles at 1 AU to answer the  following questions:  - What is the speed range at which nanometer sized particles impact

This information comes from the dataset README covering the NTA data and associated metadata for this dataset. Dust samples were collected from home vacuum bags and sieved (<150 µm). Internal standard (MPFAC-MXA, Wellington Labs) was spiked , dependent on dust mass, to a concentration of 10 ng/g. Native standards (PFAC-MXA in methanol, Wellington Labs) were dosed into each calibration and QC standard. The next day, 5 ml methanol was added to each sample. Samples were sonicated, centrifuged, and cleaned up. Samples were then blown down using a dry nitrogen gas stream not to dryness; samples were reconstituted to 0.5 ml with methanol as needed. A 100 µl aliquot of sample extract was combined with 300 µl mobile phase A (see below). Sample extracts were analyzed by UHPLC-MS/MS on a Thermo Scientific (Waltham, MA) system consisting of a TriPlus RSH autosampler/injector, Vanquish Horizon UPLC/pump system, and Thermo Orbitrap Fusion tribrid mass spectrometer. Chromatographic separation was performed using a Restek (Bellefonte, PA) Raptor C18 column at 55 °C. A 15-minute reverse-phase gradient was applied consisting of mobile phases A (95:5 v/v deionized water:methanol containing 2.5 mM ammonium acetate) and B (5:95 v/v deionized water:methanol containing 2.5 mM ammonium acetate). Negative-polarity electrospray ionization [ESI (-)] was applied first, with positive-polarity applied afterwards. Mass spectra were collected using a resolving power of 50,000, with preferred-ion data-dependent acquisition (DDA) applied to select molecular features for MS2 fragmentation. Samples were analyzed in a single batch. The full batch was repeated twice with randomized sample order. Separate batches were run for ESI(+) and ESI(-) analysis, for a total of six sample batches. Targeted methanolic calibration standards at concentrations of 1-1000 ng/g Wellington PFAC-MXA PFAS mixture were run at the start and end of the first batch. Method blanks, QC standards, pooled samples, and solvent-only blanks were run every ten samples across all batches. After data collection, chromatograms were processed and peak areas integrated in Thermo Scientific Xcalibur Quan Browser 4.3 for targeted quantitation. For nontargeted identification, chromatograms and associated mass spectra were processed in Thermo Scientific Compound Discoverer 3.3. Features were prioritized for expert identification based on a combination of high maximum abundance, strong match to library spectra, negative mass defect (for PFAS), presence as a member of a likely hologous series (for PFAS and surfactants); and/or presence of diagnostic PFAS-related fragments in their MS2 spectra. Overall, 742 features of interest at confidence 1-3 were identified, as well as 7 confidence-5 features meriting inclusion in the final dataset, and excluding hundreds of features representing false positives/adducts/etc. tentatively identified by Compound Discoverer.

Our study focuses on the hardiest microorganisms inhabiting the ISS in order to assess their diversity and capabilities to resist certain stresses. We specifically selected dust samples from the Russian modules that were obtained 8-10 years ago and stored since then under sealed conditions on Earth. Targeting long-time survivors and spore-forming microorganisms we assessed consequently the cultivable microbial community of these samples in order to obtain model microbial strains that could help to analyze specific adaptation towards environmental stresses such as desiccation and lack of nutrients. In this study we analyzed these microorganisms with respect to their resistance towards thermal stress and exposure to clinically relevant antibiotics. In addition we assessed the bacterial and archaeal community via molecular methods (NGS sequencing) and compared our new data with the previously derived information from the ISS microbiome.

Version 1.1 =========== This data set, ULY-D-UDDS-5-DUST-V1.1, differs slightly from the data set UL-D-UDDS-5-DUST-V1.0 created and reviewed at the PDS/Small Bodies Dust Subnode. In addition to the change in Data set ID, the following changes have been made:

Version 1.1 =========== This data set, ULY-D-UDDS-5-DUST-V1.1, differs slightly from the data set UL-D-UDDS-5-DUST-V1.0 created and reviewed at the PDS/Small Bodies Dust Subnode. In addition to the change in Data set ID, the following changes have been made:

Soil and air concentrations of asbestos in Sumas study. This dataset is associated with the following publication: Wroble, J., T. Frederick, A. Frame, and D. Vallero. Comparison of soil sampling and analytical methods for asbestos at the Sumas Mountain Asbestos Site—Working towards a toolbox for better assessment. PLoS ONE. Public Library of Science, San Francisco, CA, USA, 12(7): e0180210, (2017).