Ion Sponge: A 3‑Dimentional Array of Quadrupole Ion Traps for Trapping and Mass-Selectively Processing Ions in Gas Phase

In this study, the concept of ion sponge has been explored for developing 3D arrays of large numbers of ion traps but with simple configurations. An ion sponge device with 484 trapping units in a volume of 10 × 10 × 3.2 cm has been constructed by simply stacking 9 meshes together. A single rf was used for trapping ions and mass-selective ion processing. The ion sponge provides a large trapping capacity and is highly transparent for transfer of ions, neutrals, and photons for gas phase ion processing. Multiple layers of quadrupole ion traps, with 121 trapping units in each layer, can operate as a single device for MS or MS/MS analysis, or as a series of mass-selective trapping devices with interlayer ion transfers facilitated by AC and DC voltages. Automatic sorting of ions to different trapping layers based on their mass-to-charge (<i>m</i>/<i>z</i>) ratios was achieved with traps of different sizes. Tandem-in-space MS/MS has also been demonstrated with precursor ions and fragment ions trapped in separate locations

Immobilization of Ionic Liquids onto the Poly(vinylidene fluoride) by Electron Beam Irradiation

An unsaturated room-temperature ionic liquid (IL), 1-vinyl-3-butylimidazolium chloride [VBIM]­[Cl], has been grafted onto poly­(vinylidene fluoride) (PVDF) by electron beam irradiation at room temperature. The structure and physical properties of IL grafted PVDF (PVDF-<i>g</i>-IL) were investigated. Both the extraction experiments and ¹H NMR results indicated the successful grafting of IL onto PVDF molecular chains. It was calculated that IL grafting yield was approximately 3.9 per 100 repeating units of PVDF, suggesting very short IL grafting sequences. The melting temperatures (<i>T</i>_m) of the PVDF-<i>g</i>-IL films decreased with absorbed dose, suggesting the occurrence of crystal defects of PVDF caused by the irradiation. However, the morphologies, crystal forms and crystal long periods (<i>L</i>) of PVDF-<i>g</i>-IL films were not significantly influenced by the irradiation. Moreover, the effects of IL grafting and absorbed dose on physical properties of PVDF-<i>g</i>-IL films were investigated. It was found that the irradiation could immobilize IL molecules onto PVDF chains and thus suppressed their migration in electric filed. Therefore, the grafted samples showed lower dielectric loss, electrical conductivity as well as dielectric permittivity compared with the unirradiated blends. Moreover, the elongation at break of the grafted PVDF decreased with the applied irradiation dose, but the Young’s modulus increased. The as-prepared PVDF-<i>g</i>-IL composites exhibited large dielectric permittivity, low dielectric loss and, in particular, excellent toughness, which is promising for use in dielectric capacitor applications

Engineering Reduced Graphene Oxide Aerogel Produced by Effective γ‑ray Radiation-Induced Self-Assembly and Its Application for Continuous Oil–Water Separation

Reduced graphene oxide aerogel (RGO aerogel) is successfully synthesized via simultaneous reduction and self-assembly of graphene oxide (GO) sheets under γ-ray irradiation. As the resulting RGO aerogel possesses an interconnected macroporous structure with strong hydrophobicity and oleophilicity, it has great potential in oil–water separation. Adsorption–distillation and adsorption–combustion are both utilized to treat oil floating on water or oil sinking below the water surface. More importantly, a simple device has been developed to adsorb continuously and collect floating oil, and it has shown great promise for practical application

Preparation of flexible graphene@SnO₂ composite fiber via in situ chemical reduction and self-assembly method

<p>A facile in-situ chemical reduction and self-assembly method was developed to prepare graphene and tin oxide (graphene@SnO₂) composite fibers. The obtained graphene@SnO₂ fiber exhibits excellent tensile mechanical performance with high mechanical strength and superior plastic deformation (mechanical strength up to 65 MPa with an ultimate elongation about 7%). The electrical resistance of the graphene@SnO₂ fiber holds steady and has a negligible change in either the bent or straight status over 100 cycles. In the prepared composite fibers, SnO₂ nanoparticles with sizes of 3–5 nm homogeneously dispersed on the graphene sheets. The conductivity of GF@SnO₂ was about 6.0–2.5 S/cm with the increase content of Sn⁴⁺ due to the tin oxide semiconductor doping.</p

Synthesis of Few-Layer Reduced Graphene Oxide for Lithium-Ion Battery Electrode Materials

We report here a rapid and cost-effective approach to synthesize few-layer reduced graphene oxide (FL-RGO) in graphene oxide solution using EDA as a reducing agent and a cross-linker, and where the resulting FL-RGO was characterized by means of AFM, TEM, XPS, UV–vis, and XRD spectroscopies. A mechanism for forming the FL-RGO via removal of epoxide and hydroxyl groups from GO and stitching of the GO sheets by EDA in a water solution was proposed. FL-RGO was also tested as the electrolyte for a Li⁺-ion battery and showed advantages with a 346 mAh g^–1 capacity at a charge/discharge current density of 1C even after 60 cycles, which is comparable to the theoretical capacity of the graphite (372 mAh g^–1)

Mini 12, Miniature Mass Spectrometer for Clinical and Other ApplicationsIntroduction and Characterization

A benchtop miniature mass spectrometer system, Mini 12, with ambient ionization source and tandem mass spectrometry capabilities has been developed and characterized. This instrument was developed as a self-contained system to produce quantitative results for unprocessed samples of small volumes including nonvolatile analytes. The ion processing system, vacuum system, and control system are detailed. An integrated sample loading system facilitates automated operation. A user interface has been developed to acquire and to interpret analytical results for personnel who have limited mass spectrometry knowledge. Peak widths of Δ<i>m</i>/<i>z</i> 0.6 Th (full width at half-maximum) and a mass range of up to <i>m</i>/<i>z</i> 900 are demonstrated with the rectilinear ion trap mass analyzer. Multistage experiments up to MS⁵ are accomplished. Consumable cartridges have been designed for use in ambient paper spray ionization, and the recently developed extraction spray ionization method has been employed to improve the quantitative performance. Monitoring of trace-levels of chemicals in therapeutic drugs, as well as in food safety and environmental protection operations is demonstrated. Dual MS/MS scans are implemented to obtain the intensities of the fragment ions from the analyte and its internal standard, and the ratio is used in quantitative analysis of complex samples. Limits of quantitation (LOQ) of 7.5 ng/mL, with relative standard deviations below 10%, have been obtained for selected therapeutic drugs in whole blood throughout their individual therapeutic ranges

Graphene Oxide Transparent Hybrid Film and Its Ultraviolet Shielding Property

Herein, we first reported a facile strategy to prepare functional Poly­(vinyl alcohol) (PVA) hybrid film with well ultraviolet (UV) shielding property and visible light transmittance using graphene oxide nanosheets as UV-absorber. The absorbance of ultraviolet light at 300 nm can be up to 97.5%, while the transmittance of visible light at 500 nm keeps 40% plus. This hybrid film can protect protein from UVA light induced photosensitive damage, remarkably