[en] Differential ion mobility spectrometry (DMS) spatially separates ions in the gas phase using the mobility differences of the ions under applied low and high electric fields. The use of DMS as an ion filter (or ion selector) prior to mass spectrometry analysis has been compromised by the limited ion transmission efficiency. This paper reports enhancement of the DMS-MS sensitivity and signal stability using a modified CaptiveSpray™ source. In terms of the ion sampling and transmission efficiency, the modified CaptiveSpray source swept ~ 89% of the ions generated by the tapered capillary through the DMS device (compared to ~ 10% with a conventional microspray source). The signal fluctuation improved from 11.7% (relative standard deviation, RSD) with microspray DMS-MS to 3.6% using CaptiveSpray-DMS-MS. Coupling of LC to DMS-MS via the modified CaptiveSpray source was simple and robust. Using DMS as a noise-filtering device, LC-DMS-MS performed better than conventional LC-MS for analyzing a BSA digest standard. Although LC-DMS-MS had a lower sequence coverage (55%), a higher Mascot score (283) was obtained compared to those of LC-MS (sequence coverage 65%; Mascot score 192) under the same elution conditions. The improvement in the confidence of the search result was attributed to the preferential elimination of noise ions. .

[en] A solid-phase microextraction (SPME) fiber coated with a hollow microporous organic network (H-MON) was fabricated for the analysis of short-chain chlorinated paraffins (SCCPs). The sorbent was prepared by reacting tetra(4-ethynylphenyl)methane and 1,4-diiodobenzene using bis-(triphenylphosphine) palladium(II) as the catalyst in the presence of silica sphere templates, which then were removed by hydrofluoric acid. The SCCPs were quantified by GC-MS working in the negative chemical ionization mode. The H-MON has a high specific surface (701 m²·g⁻¹) and microporosity (pore size <2 nm). Extraction temperature, extraction time, and ionic strength of the sample solutions were optimized by using the Box-Behnken design. The head-space SPME exhibits better extraction performance than the direct immersion mode. Under optimal working conditions, the detection limit (3 times of the standard deviation) is 0.03 ng·mL⁻¹ in the water samples. Response is linear in the 0.05–10 ng·mL⁻¹ concentration range. Repeatability and reproducibility, expressed as the relative standard deviations, ranged from 4.6 to 11.0%. The method was successfully applied in the analysis of SCCPs in water, sediments, organisms, and atmospheric particulate matter samples. .

[en] This Letter focuses on perturbation to form invariance of mechanico-electrical systems. Criteria and structural equations for form invariance after disturbance are proposed. Considering perturbation of all the infinitesimal generators, a new type of adiabatic invariant induced by perturbation to form invariance of the system is reported.

[en] Mesoporous carbon hollow spheres coated with MoS₂ (C@MoS₂) were synthesized to obtain a material with large specific surface area, fast electron transfer efficiency and good water dispersibility. The composite material was applied as a matrix for the analysis of small molecules by surface-assisted laser desorption/ionization time-of-flight mass spectrometry (SALDI-TOF MS). The use of a core-shell C@MoS₂ matrix strongly reduces matrix background interferences and increases signal intensity in the analysis of sulfonamides antibiotics (SAs), cationic dyes, emodin, as well as estrogen and amino acids. The composite material was applied to the SALDI-TOF MS analysis of selected molecules in (spiked) real samples. The ionization mechanism of the core-shell C@MoS₂ as a matrix is discussed. The method exhibits low fragmentation interference, excellent ionization efficiency, high reproducibility and satisfactory salt tolerance.

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[en] In this work, sorbent-attached membrane funnel-based spray ionization mass spectrometry was explored for quantitative analysis of anti-diabetic drugs spiked in human plasma. C_1_8-attached membrane funnel was fabricated for in situ extraction and clean-up to alleviate matrix suppression effect in the ionization process. Repaglinide was used as a target analyte of anti-diabetic drugs. Under optimal working conditions, good linearity (R"2 > 0.99) was obtained in the concentration range of 1–100 ng mL"−"1. The method detection limit of target drugs spiked in the human plasma was around 0.30 ng mL"−"1. Through the application of an isotope-labeled internal standard, the signal fluctuation caused by residual background matrices was largely alleviated and the precision of measurement (RSD) was below 15%. The recovery of repaglinide for 5, 25, and 100 ng mL"−"1 of spiked human plasma matrixes ranged from 87% to 112%. The developed method was successfully applied to determine repaglinide in plasma volunteers who orally received a dose of drug association. Our results demonstrated that membrane funnel-based spray is a simple and sensitive method for rapid screening analysis of complex biological samples. - Highlights: • Sorbent attached membrane funnel based spray platform was used for drug determination in human plasma. • The matrix suppression effect of human plasma was largely eliminated. • The method was applied to determine repaglinide in plasma volunteers. • Membrane funnel-based spray is promising for analysis of biological samples.

[en] The authors describe the in-situ hydrothermal growth of a porphyrinic zirconium metal-organic framework (MOF), referred to as PCN-222(Zr), on stainless steel fibers. The PCN-222(Zr) is uniformly deposited on the fiber and displays exceptional thermal and chemical stability. The coated fiber was used for the solid-phase microextraction of nitrated polycyclic aromatic hydrocarbons (NPAHs) in water sample prior to their quantitation by gas chromatography in combination with negative chemical ionization mass spectrometry. Limits of detection (S/N = 3) of 17 selected analytes ranged from 0.10 to 20 ng·L⁻¹. Linear range was from 0.4 to 400 ng·L⁻¹. Intra- and inter-day reproducibility values obtained from a single fiber (six replicates) ranged from 2.2–12.8% and 3.6–12.1%, respectively. Fiber-to-fiber reproducibility for six parallel fibers ranged from 3.3% to 10.3% under the same working conditions. The method was successfully applied to determine NPAHs in environmental water, atmospheric particulate matter (PM2.5), and soil samples. This work demonstrated a prominent prospect of this kinds of stable MOF for applications in extraction techniques. .

[en] Highlights: • Prenatal exposure to PM_2.5 reduced adipocyte size of eWAT in male offspring. • The decreasing levels of pro-inflammatory cytokines were found in adipose tissue. • The expression of genes involved in fatty acid synthesis and oxidation were reduced. • A disrupted metabolism of lipids was found in adipose tissue. -- Abstract: Prenatal exposure to ambient fine particles (diameter < 0.25 μm, PM_2.5) has been found to be associated with abnormal growth and development in offspring. However, the effects of PM_2.5 on the lipid metabolism of adipose tissue in offspring are unclear. In the present study, we established a mouse model of prenatal exposure to PM_2.5 by intratracheal instillation to pregnant C57BL/6 female mice with PM_2.5 suspension or normal saline. We found that prenatal exposure to PM_2.5 of a mouse model reduced body weight in adult male offspring after 6 weeks old. Histological analysis showed that the adipocyte size was significantly reduced in epididymal adipose tissue (eWAT) in male offspring, but not in brown adipose tissue. The expression levels of genes related to fatty acid synthesis (ACC1, ACSL1) and oxidation (PPARα) in eWAT were also significantly decreased. In addition, downregulation of pro-inflammatory cytokines (TNFα, IL-1β, IL-6) was also observed. Lipidomics analysis of eWAT demonstrated that prenatal exposure of PM_2.5 reduced lysophosphatidylcholines (LPC), phosphatidylcholines (PC), phosphatidylethanolamines (PE), sphingomyelins (SM), and ceramides (Cer), indicating that metabolic pathways, including SM-Cer signaling and glycerophospholipids remodeling, were disrupted. In summary, prenatal exposure to PM_2.5 was associated with the dysregulations in lipid metabolism of eWAT and pro-inflammatory response in male offspring.

[en] The adsorptive potential of hexagonal boron nitride nanosheets (h-BNNSs) for solid-phase extraction (SPE) of pollutants was investigated for the first time. Seven indicators of polychlorinated biphenyls (PCBs) were selected as target analytes. The adsorption of PCBs on the surface of the h-BNNSs in water was simulated by the density functional theory and molecular dynamics. The simulation results indicated that the PCBs are adsorbed on the surface by π–π, hydrophobic, and electrostatic interactions. The PCBs were extracted with an h-BNNS-packed SPE cartridge, and eluted by dichloromethane. Gas chromatography–tandem mass spectrometry working in the multiple reaction monitor mode was used for the sample quantification. The effect of extraction parameters, including the flow rate, pH value, breakthrough volume, and the ionic strength, were investigated. Under the optimal working conditions, the developed method showed low limits of detection (0.24–0.50 ng L"−"1; signal-to-noise ratio = 3:1), low limits of quantification (0.79–1.56 ng L"−"1; signal-to-noise ratio = 10:1), satisfactory linearity (r > 0.99) within the concentration range of 2–1000 ng L"−"1, and good precision (relative standard deviation < 12%). The PCBs concentration in environmental water samples was determined by the developed method. This results demonstrate that h-BNNSs have high analytical potential in the enrichment of pollutants. - Highlights: • The hexagonal boron nitride nanosheets were synthesized. • The nanosheets were used as adsorbent for solid-phase extraction. • The h-BN demonstrates remarkable adsorption of PCBs from water samples. • The method was successfully applied in determination of PCBs in water samples.

[en] Graphical abstract: QDSSCs with different structure: (a) J-V curves, (b) TRPL spectra. - Highlights: • Charge generation, separation and transfer performance have been balanced by different structures. • Excellent charge separation and transfer performance have been exhibited for nano-array structure. • Nanotube array structure relative better charge generation, excellent charge separation and transfer performance of QDSSCs. - Abstract: TiO₂ nanoparticle and nano-array structures including nanorods, nanowires and nanotubes are prepared for the photo-electrodes of CuInS₂ quantum dot sensitized solar cells, which are investigated the balance on charge generation, separation and transfer performance in solar cells. The optical absorption properties and PL spectra of different photo-electrodes are investigated, which indicates better charge generation property for nanoparticle structure and better charge separation property for nano-arrays structure. With the grain boundary of nanoparticle films and excellent charge transfer performance of nano-arrays films, higher short-circuit current density value has been performed for all the nano-array structure based solar cells. Due to the relative large surface area of three nano-arrays structure for charge generation, excellent charge separation and transfer performance, the TiO₂ nanotube based CuInS₂ quantum dot sensitized solar cells exhibits greater photovoltaic efficiency than other nanostructures, which can support the progress for further photovoltaic performance enhancement on quantum dot sensitized solar cells.

[en] Highlights: • The adsorbent was prepared by directly adsorbing dithizone on the graphene. • Application in speciation of mercury in real water samples with complex matrix • High enrichment factors, low LODs and wide linearity were provided. • High resistance to matrix interference was obtained by introducing dithizone. -- Abstract: A facile method of magnetic solid-phase extraction high-performance liquid chromatography-inductively coupled plasma mass spectrometry (MSPE-HPLC-ICP-MS) based on a magnetic adsorbent that was prepared by simply and directly adsorbing dithizone on the surface of the magnetite-reduced graphene oxide composites was developed to preconcentrate trace mercury species in environmental samples. Parameters influencing the synthesis of the adsorbents and extraction, including the ratio of GO to iron (III) acetylacetonate, solution pH, adsorption time, desorption time and the component of the eluent, were optimized. Under the optimized conditions, the enrichment factors were 400 and 380 (400 mL water sample) for inorganic mercury (IHg) and methylmercury (MMHg), respectively. The detection limits (3δ) of the proposed method were 0.48 and 0.17 ng L⁻¹ for IHg and MMHg. The spiked recoveries (91.5–111%) and standard deviation ( < 3.1%) in real water samples indicated that the method had high reproducibility and accuracy. This proposed MSPE-HPLC-ICP-MS method, with simple operation, high enrichment factors and high sensitivity, was successfully applied for the determination of mercury species at trace levels in environmental water samples, including river water, ground water, sea water and sewage effluent, and fish samples.