Effective extraction of the metabolites of toluene and xylene based on a postsynthetic-modified magnetic covalent organic polymer

Pd nanoparticles-functionalized In2O3 based gas sensor for highly selective detection of toluene

Given the threat posed by toluene to human health and environmental safety, real-time and efficient detection of toluene assumes paramount importance. However, the low chemical reactivity and structural similarity of benzene, toluene, and xylene (BTX) gases impede the attainment of highly selective toluene detection. Herein, palladium-loaded indium oxide nanospheres were successfully synthesized through a combination of solvothermal and post-reduction methods. And the sensor based on 0.75 wt% Pd-In2O3 exhibits the response to the concentration of 100 ppm toluene (Ra/Rg = 21) that is approximately four times better compared to pure indium oxide (Ra/Rg = 4) at their respective optimum operating temperatures. Moreover, this sensor exhibited enhanced sensing performance towards toluene, including a low operating temperature of 160 °C, exceptional selectivity, and good stability. Furthermore, an investigation into the sensing mechanism of toluene by the Pd-In2O3-based sensor was conducted. The chemical and electron sensitization effects of palladium result in the more chemisorbed oxygen of the sensing material, which improves the toluene sensing performance by enhancing the reaction with more toluene molecules. Additionally, the moderate catalytic activation of toluene by palladium plays a crucial role in improving the selectivity. Overall, this work provides a basis for the rational design of metal oxide semiconductor sensors with catalytic properties for the highly selective detection of toluene.

Design of Ce3+ ions functionalized magnetic black phosphorus nanosheets for highly efficient enrichment of phosphopeptides

BACKGROUND

The abnormal variation of phosphorylation can lead to many human diseases, such as Alzheimer's disease and cancer. Because of its high throughput and rapidity, mass spectrometry (MS)-based method has been widely used to characterize phosphopeptides/phosphoproteins in complex biological samples. However, the direct MS analysis for phosphopeptides is still a challenging task due to the complexity of biological samples and the signal suppression of abundant non-phosphopeptides. Therefore, an efficient enrichment platform for low-abundance phosphopeptide capture and detection is in great demand.

RESULTS

In this study, Ce3+ ions functionalized magnetic black phosphorus nanosheets were successfully synthesized and characterized. The prepared magnetic material had high surface area (185.80 m2 g-1), good hydrophilicity (12.15°), and magnetic property (33.38 emu g-1). The magnetic material provided abundant affinity sites for phosphopeptide enrichment through immobilized metal ion affinity chromatography (IMAC). By combining MS analysis, the method exhibited satisfactory performance, including high sensitivity (0.1 fmol), good selectivity (α-casein: β-casein: BSA = 1: 1: 5000), and high recovery (87.2 %). The method was applied to enrich and detect phosphopeptides in skimmed milk, human saliva, serum, and A549 cell lysate, proving its feasibility for phosphopeptide analysis. Additionally, the method provided the sequence motifs of the captured phosphopeptides and the biological functions of the phosphoproteins in A549 cell lysate.

SIGNIFICANCE

This work presented a facile analysis platform for phosphopeptides, including sample preparation, enrichment process, and MS detection. The analysis strategy was successfully adopted for capturing and analyzing phosphopeptides from stranded proteins and complex bio-samples. This work presents a novel approach for the design and construction of black phosphorus-based adsorbents in phosphoproteomics research.

Construction of magnetic recoverable porous electron-rich organic frameworks for efficiently enrichment of phenylurea herbicides from water and milk samples prior to HPLC detection

Porous electron-rich organic frameworks have attracted an increased attention in the adsorption and removal of pollutants due to their abundant electron-rich nitrogen atoms, which can effectively interact with positively charged substance. In this study, a porous electron-rich organic framework (Car-POF) and positively charged amino-functionalized magnetic nanoparticles (Fe3O4-NH2) were used to construct a magnetic electron-rich Fe3O4-NH2@Car-POF for the enrichment of some phenylurea herbicides from water and milk samples prior to high performance liquid chromatographic detection. The adsorption capacity of Fe3O4-NH2@Car-POF for the phenylureas ranged from 14.93 to 28.83 mg g-1. The LODs were observed in the range of 0.05-0.20 ng mL-1 and 0.5-1.5 ng mL-1, and LOQs in the range of 0.17-0.66 ng mL-1 and 1.7-5.0 ng mL-1 for water and milk samples with RSD less than 9.0. The adsorption studies with cationic and anionic dyes revealed that Fe3O4-NH2@Car-POF is favorable for the adsorption of positively charged compounds.

Polyoxometalate functionalized magnetic metal-organic framework with multi-affinity sites for efficient enrichment of phosphopeptides

The reasonable design of metal-organic framework (MOF)-derived nanomaterial has important meaning in increasing the enrichment efficiency in the study of protein phosphorylation. In this work, a polyoxometalate (POM) functionalized magnetic MOF nanomaterial (Fe3O4@MIL-125-POM) was designed and fabricated. The nanomaterial with multi-affinity sites (unsaturated metal sites and metal oxide clusters) was used for the enrichment of phosphopeptides. Fe3O4@MIL-125-POM had high-efficient enrichment performance towards phosphopeptides (selectivity, a mass ratio of bovine serum albumin/α-casein/β-casein at 5000:1:1; sensitivity, 0.1 fmol; satisfactory repeatability, ten times). Furthermore, Fe3O4@MIL-125-POM was employed to enrich phosphopeptides from non-fat milk digests, saliva, serum, and A549 cell lysate. The enrichment results illustrated the great potential of Fe3O4@MIL-125-POM for efficient identification of low-abundance phosphopeptides.

Molecularly imprinted electrochemical sensor based on CoNi-MOF/RGO nanocomposites for sensitive detection of the hippuric acid

Toluene, a volatile organic compound, may have adverse effects on the nervous and digestive system when inhaled over an extended period. The assessment of environmental toluene exposure can be effectively conducted by detecting hippuric acid (HA), a toluene metabolite. In this investigation, a molecularly imprinted electrochemical sensor was developed for HA detection, utilizing the synergistic effects of reduced graphene oxide (RGO) and a bimetallic organic skeleton known as CoNi-MOF. Initially, graphene oxide (GO) was synthesized using a modified Hummers' method, and RGO with better conductivity was achieved through reduction with ascorbic acid (AA). Subsequently, CoNi-MOF was introduced to enhance the material's electron transport capabilities further. The molecularly imprinted membrane was then prepared via electropolymerization to enable selective HA recognition. Under optimal conditions, the synthesized sensor exhibited accurate HA detection within a concentration range of 2-800 nM, with a detection limit of 0.97 nM. The sensor's selectivity was assessed using a selectivity coefficient, yielding an imprinting factor of 6.53. The method was successfully applied to the quantification of HA in urine, demonstrating a favorable recovery rate of 93.4%-103.9%. In conclusion, this study presents a practical platform for the detection of human metabolite detection.

Cerium ions immobilized magnetic graphite nitride decorated with L-Alanyl-L-Glutamine as new chelator for enrichment of phosphopeptides

Cerium ions immobilized magnetic graphite nitride material have been prepared using L-Alanyl-L-Glutamine as the new chelator. The resulting Fe3O4/g-C3N4-L-Ala-L-Gln-Ce4+, as an immobilized metal ion affinity chromatography (IMAC) sorbent, was reusable. This is due to the strong coordination interaction between L-Alanyl-L-Glutamine and cerium ions. After a series of characterizations, the magnetic nanocomposite showed high surface area, good hydrophilicity, positive electricity, and magnetic response. Fe3O4/g-C3N4-L-Ala-L-Gln-Ce4+ had high sensitivity (0.1 fmol), selectivity (α-/β-casein/bovine serum albumin, 1:1:5000), and good recyclability (10 cycles). A total of 647 unique phosphopeptides mapped to 491 phosphoproteins were identified from A549 cell lysate by nano LC-MS analysis.

Effective Enrichment of Phosphopeptides Using Magnetic Polyoxometalate-Based Metal-Organic Frameworks

In this study, magnetic polyoxometalate-based metal-organic frameworks (Fe3O4-POMOFs) were designed and applied to the enrichment of phosphopeptides. Thanks to the abundant metal oxide and metal ion sites, the material had a strong affinity for phosphopeptides. Simultaneously, the high amount of amino and guanidyl groups provided hydrophilicity and positive charge for phosphopeptide capture. By coupling with MS detection, the established platform possessed good reusability, high sensitivity (0.01 fmol), and high selectivity (α-casein/β-casein/bovine serum albumin = 1:1:5000). Furthermore, the method was successfully used for the detection of phosphopeptides in nonfat milk, human serum, saliva, and A549 cell lysate, showing great potential for practical application.