Monthly Archives: January 2024

Direct Analysis of Whole Blood by a Disposable Monolithic Column Mass Spectrometry Analysis Kit

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Direct Analysis of Whole Blood by a Disposable Monolithic Column Mass Spectrometry Analysis Kit†

A disposable monolithic column mass spectrometry analysis kit was developed for direct whole blood analysis. The monolithic column can clean whole blood matrix in 30 s as well as avoid analyte exposure to oxygen, moisture and sunlight for sample storage. This MS kit has been successfully applied to the quantitative analysis of procainamide hydrochloride in 2 μL rat blood, proving it a cost-effective and powerful tool for in vitro diagnostics in the future.


Comprehensive Summary

A monolithic column-based mass spectrometry (MS) analysis kit was prepared for whole blood analysis with MS. The kit is disposable and can be used for purification, storage, transportation and direct analysis of whole blood. The kit mainly consists of a capillary for quantitative microsampling, a cation exchange monolithic column for purification and storage, and a syringe for loading sample. This kit is very friendly to various users that one can easily siphon the blood in the kit followed by rapid clean-up. We established a quantitative method using the kit with a limit detection as low as 0.33 nmol/L, and achieved more than five orders of magnitude enhancement in sensitivity compared to direct nanoelectrospray ionization MS analysis. The column can avoid analyte exposure to environment, which helps the storage of the sample for laboratory analysis. The relative standard deviation of immediate blood analysis and storage blood analysis within 10 d was less than 10%. This method has been successfully applied to the quantitative analysis of procainamide hydrochloride in 2 μL rat blood. These results indicate that this disposable kit does have the potential to achieve highly sensitive quantitative MS analysis in biological samples, which is expected to become a cost-effective and powerful tool for in vitro diagnostics.

Ru(II)‐Catalyzed ortho C—H Allylation of N‐Aryl‐7‐azaindoles with 2‐Methylidene Cyclic Carbonate

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Ru(II)-Catalyzed ortho C—H Allylation of N-Aryl-7-azaindoles with 2-Methylidene Cyclic Carbonate

We used Ru(II)-catalyst to perform ortho C—H allylation of N-aryl-7-azaindole with 2-methylenecyclic carbonate. The range of reactions is quite wide, and reactions can also be carried out on other heterocyclic compounds, and different carbonates can be used.


Comprehensive Summary

A Ru(II)-catalyzed ortho allylation reaction of N-aryl-7-azaindole with readily available 2-methylidene cyclic carbonate has been developed. This reaction is an effective pathway for synthesizing 7-azaindole derivatives with a wide scope of substrates and high yields. In addition, the method can be extended to the allylation of other heterocyclic compounds and several cyclic carbonates, highlighting the practicality of this strategy for synthesis.

Abatement of volatile organic compounds employing a thermoplastic nano‐photocatalyst layered on a glass reactor

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Abatement of volatile organic compounds employing a thermoplastic nano-photocatalyst layered on a glass reactor

Volatile Organic Compounds (VOCs) represent a wide class of dangerous pollutants. Here, a new gas-flow photoreactor coated with a thermoplastic TiO2-based nanocomposite is developed and used in the solar-triggered photocatalytic degradation of common VOCs. The peculiar design of the reactor combined with the features of the coating nanosystem provides a cheap and efficient way to boost the abatement of VOCs.


Abstract

Industrial development and urbanization have increased the emission of Volatile Organic Compounds (VOCs) into the atmosphere, causing environmental and health risks. Several approaches are used for their abatement, including chemical, thermo- and photo-catalytic oxidations, but they are not fully satisfactory. In this work, a thermoplastic TiO2-based photo-catalyst was used as a coating layer of a glass-reactor. Solar-triggered photocatalytic degradation of ethanol, toluene, and acetone (used as model VOCs) highlights the better performance of the coated photoreactor than that of TiO2 nanopowder. The influence of the pollutant flow rate on the photodegradation performance of the system was also investigated, revealing an inverse relationship between degradation and flow rates. The experimental data suggest that our approach provides a cost-effective and efficient way to boost the abatement of VOCs, useful for further industrial-scale applications. The morphology and the compositional homogeneity of the nanocomposite coating were addressed through Field Emission Scanning Electron Microscopy coupled with Energy Dispersive X-ray Analysis.

Computational Modelling and Mechanistic Insight into Light‐Driven CO Dissociation of Square‐Planar Rhodium(I) Complexes

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Computational Modelling and Mechanistic Insight into Light-Driven CO Dissociation of Square-Planar Rhodium(I) Complexes

C−H activation: Rh-phosphine complexes can activate C−H bonds in otherwise unreactive alkanes. Quantum chemical calculations provide mechanistic insights into the generation of the active species which is formed via the light-induced CO dissociation at Rh(I) complexes featuring trimethylphosphine and 1,2-bis(dimethylphosphino)ethane. The calculations align well with experimental photochemical studies on the Rh(I) complexes.


Abstract

The activation step of Vaska-type Rh(I) complexes, such as the photocleavage of the Rh−CO bond, plays an important role in the subsequent C−H activation. To elucidate the details of the photochemistry of Vaska-type Rh(I) complexes, such as trans-Rh(PMe3)2(CO)(Cl), we here present a computationally derived picture as obtained at the density functional level of theory in combination with multireference wavefunction-based methods. We have identified that the photocleavage of CO proceeds via the metal-centered excited state (3MC, ), which is populated through intersystem crossing from the dipole-allowed excited state S1( - ). Moreover, the present study unraveled the reasons for the low C−H activation efficiency when using Rh featuring the bidentate ligand 1,2-bis(dimethylphosphino)ethane (dmpe), namely due to its unfavorable photochemical properties, i. e., the small driving force for light-induced CO loss and the fast deactivation of 3MC state back to the singlet ground state. In this study, we provide theoretical insight into mechanistic details underlying the light-induced CO dissociation process, for Rh complexes featuring PMe3 and dmpe ligands.

Organic fluorophores with large Stokes shift for bioimaging and biosensing

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Organic fluorophores with large Stokes shift for bioimaging and biosensing

The review has systematically summarized several methods recently developed to increase Stokes shift of fluorophores by structural modification, and highlighted typical applications of fluorophores with large Stokes shift in single-excitation multi-color imaging and ratiometric imaging. The review will provide a theoretical guidance for the design of novel fluorophores with large Stokes shift.


Abstract

Fluorophores and fluorophores-based probes or labels can visualize the structures and content fluctuations of biomolecules, and have made great progress in the broad range of biomedicine fields. However, many commercially available fluorophores suffer from small Stokes shift, which results in insufficient signal-to-noise ratio and self-quenching in advanced imaging techniques. Moreover, the small Stokes shift also hinders the application of fluorophores in some complex imaging, such as single-excitation multicolor imaging. In the past two decades, many effects have been made to enlarge Stokes shift of fluorophores. In this review, we clarified the reasons for the small Stokes shift building on the structural analysis of fluorophores, systematically summarize the methods of structural modification to increase Stokes shift, and present some representative applications of fluorophores with large Stokes shift in imaging and sensing.

Syngas Production by Chemical Looping Dry Reforming of Methane over Ni‐modified MoO3/ZrO2

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Syngas Production by Chemical Looping Dry Reforming of Methane over Ni-modified MoO3/ZrO2

Ni-modified molybdenum zirconia (Ni/MoO3/ZrO2) was developed as an effective oxygen storage material for chemical looping dry reforming of methane (CL–DRM) under isothermal reaction conditions of 650 °C, which was 100–200 °C lower than the previously reported oxide-based materials.


Abstract

We investigated supported-MoO3 materials effective for the chemical looping dry reforming of methane (CL–DRM) to decrease the reaction temperature. Ni-modified molybdenum zirconia (Ni/MoO3/ZrO2) showed CL–DRM activity under isothermal reaction conditions of 650 °C, which was 100–200 °C lower than the previously reported oxide-based materials. Ni/MoO3/ZrO2 activity strongly depends on the MoO3 loading amount. The optimal loading amount was 9.0 wt.% (Ni/MoO3(9.0)/ZrO2), wherein two-dimensional polymolybdate species were dominantly formed. Increasing the loading amount to more than 12.0 wt.% resulted in a loss of activity owing to the formation of bulk Zr(MoO4)2 and/or MoO3. In situ Mo K-edge XANES studies revealed that the surface polymolybdate species serve as oxygen storage sites. The Mo6+ species were reduced to Mo4+ species by CH4 to produce CO and H2. The reduced Mo species reoxidized by CO2 with the concomitant formation of CO. The developed Ni/MoO3(9.0)/ZrO2 was applied to the long-term CL–DRM under high concentration conditions (20 % CH4 and 20 % CO2) at 650 °C, with two pathways possible for converting CH4 and CO2 to CO and H2 via the redox reaction of the Mo species and coke formation.