4 research outputs found
β‑Cyclodextrin Polymer Network Sequesters Perfluorooctanoic Acid at Environmentally Relevant Concentrations
Per- and poly fluorinated
alkyl substances (PFASs), notably perfluorooctanoic
acid (PFOA), contaminate many ground and surface waters and are environmentally
persistent. The performance limitations of existing remediation methods
motivate efforts to develop effective adsorbents. Here we report a
β-cyclodextrin (β-CD)-based polymer network with higher
affinity for PFOA compared to powdered activated carbon, along with
comparable capacity and kinetics. The β-CD polymer reduces PFOA
concentrations from 1 μg L<sup>–1</sup> to <10 ng
L<sup>–1</sup>, at least 7 times lower than the 2016 U.S. EPA
advisory level (70 ng L<sup>–1</sup>), and was regenerated
and reused multiple times by washing with MeOH. The performance of
the polymer is unaffected by humic acid, a component of natural organic
matter that fouls activated carbons. These results are promising for
treating PFOA-contaminated water and demonstrate the versatility of
β-CD-based adsorbents
Terahertz Spectroscopy for Accurate Identification of Panax quinquefolium Basing on Nonconjugated 24(R)-Pseudoginsenoside F11
Panax quinquefolium is a perennial herbaceous plant that contains many beneficial ginsenosides with diverse pharmacological effects. 24(R)-pseudoginsenoside F11 is specific to P. quinquefolium, a useful biomarker for distinguishing this species from other related plants. However, because of its nonconjugated property and the complexity of existing detection methods, this biomarker cannot be used as the identification standard. We herein present a stable 24(R)-pseudoginsenoside F11 fingerprint spectrum in the terahertz band, thereby proving that F11 can be detected and quantitatively analyzed via terahertz spectroscopy. We also analyzed the sample by high-performance liquid chromatography-triple quadrupole mass spectrometry. The difference between the normalized data for the two analytical methods was less than 5%. Furthermore, P. quinquefolium from different areas and other substances can be clearly distinguished based on these terahertz spectra with a standard principal component analysis. Our method is a fast, simple, and cost-effective approach for identifying and quantitatively analyzing P. quinquefolium