Although continued growth in unconventional oil and gas production is generally projected, its long-term growth potential and sustainability have significant uncertainties. A critical problem is the low hydrocarbon recovery rates from shale and other tight formations using the horizontal well drilling and hydraulic fracturing techniques: < 10% for tight oil and ~ 20% for shale gas. Moreover, the production rate for a given well typically declines rapidly within one year. The low recoveries and declining production of shale oil and gas reservoirs are - 16 - 20 2 apparently related to the small porosity (a few to a few hundred nm) and low permeability (10 - 10 m ) of shale matrix, which make the enclosed hydrocarbon fluids difficult to access. Hence, to enhance the hydrocarbon recovery from shale matrix, it is essential to study its nanopore structure and confined fluid behavior. Small- and ultra-small-angle neutron scattering (SANS and USANS) have emerged as a powerful method for characterizing shale nanopore structure and confined fluid behavior. Owing to neutrons' high penetrating ability and high sensitivity to hydrogen (and its isotope, deuterium), SANS/USANS can probe inside shale samples to characterize nanopores from 1 nm to 10 μm in size and be readily combined with sample environmental cells to examine the fluid (hydrocarbon and water - frack fluid) behavior at relevant pressure-temperature (P-T) conditions. In this review article, an introduction is first given on the characteristics of shale matrix and the uniqueness of SANS/USANS compared with conventional methods. Then current studies on shale nanopore structure and confined fluid properties using SANS/USANS are summarized. Finally, an outlook and perspective on future research in this emerging area will be offered.

Xu, L., Huang, S., Liu, Y., Wei, S., Chen, G., Gong, Z., Ouyang, G., 2020. Hollow carbon nanobubbles-coated solid-phase microextraction fibers for the sensitive detection of organic pollutants. Analytica Chimica Acta 1097, 85-93.

http://www.sciencedirect.com/science/article/pii/S0003267019312966 Herein, a novel solid-phase microextraction (SPME)fiber based on hollow carbon nanobubbles was developed for the analysis of persistent organic pollutants. The hollow carbon nanobubbles (HCNBs), derived from the nanoscale zeoliticimidazolate framework (ZIF-8), not only possessed the ZIF-8-like microporous shell but also created an internal space for analytes storage. This architecture was beneficial to accelerating the mass transfer process and enhancing the enrichment capacity towards target analytes. As a result, the sensitivity of this HCNBs based SPME fiber toward analytes (e.g., BTEX, PAHs and PCBs) was 2 - 180 times higher compared with the commercial fibers (100 μm PDMS, 65 μm PDMS/DVB or 85 μmPA). In addition, owing to the size - selectivity of the microporous shell, the HCNBs-based SPME fiber showed high extraction ability towards target analytes with low molecule weight. Furthermore, the lifespan of the homemade fiber was evaluated to be more than 100 times attributing to the hard and stable carbon framework. Under optimal working conditions, analytical performance of the fiber towards PCBs with varying chlorination degrees showed a wide linear range - 1 - 1 (0.05 -1000 ng L ) and low LODs (0.0017 -0.0042 ng L ). Finally, the established method was successfully applied to the determinations of PCBs in three environmental water samples with good recoveries (84.5 - 117.1%).

Xu, L., Li, X., Wang, X., Song, A., Han, F., 2020. A feasible strategy based on isotopic fine structures to enhance the reliability of metabolite identification by Fourier transform ion cyclotron resonance mass spectrometry. Rapid Communications in Mass Spectrometry 34, e8560.

https://doi.org/10.1002/rcm.8560 Rationale: In the process of the identification of unknown metabolites, the most important thing is to determine their real chemical formulae according to the accurate masses which are determined by high-resolution mass spectrometry. However, high mass accuracy alone is not enough to exclude false candidates. Use of isotopic fine structures (IFSs) derived from Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) as a single further constraint could decisively determine the molecular formulae for unknown metabolites. Gastrodia elata Methods: Gastrodin, an active constituent from Bl., which can penetrate through the blood - p brain barrier and rapidly decompose to -hydroxybenzyl alcohol in the brain, was selected as a model drug. The