Synthesis and application of boronic acid-functionalized magnetic adsorbent for sensitive analysis of salbutamol residues in pig tissues.

Salbutamol (SAL) is the most widely used ß2 -agonist drug for asthma and chronic obstructive pulmonary patients, but it is also often abused as feed additive. In recent years, the abuse of SAL has led to a large number of food safety incidents. Therefore, the monitoring of SAL residues in animal products is very important. A highly selective boronate affinity magnetic adsorbent was synthesized and developed for detection of trace levels of SAL residues in pig tissue samples. The obtained Fe3O4@SiO2@FPBA(4-formylphenylboronic acid) magnetic adsorbent showed good adsorption ability to catechol and SAL, and then it was successfully applied as special magnetic solid-phase phase extraction adsorbent coupled with high-performance liquid chromatography (HPLC) for simultaneous isolation and determination of cis-diol compounds. The binding capacity of catechol and SAL reached 96 and 50 µmol/g, respectively. The method was successfully established for the detection of trace levels of SAL in pig tissue samples. The linear range extended from 0.32 to 800 µg/kg (R(2) = 0.9994). The limit of detection of SAL was 0.19 µg/kg. The recoveries were satisfactory (89.5-108.0%) at three spiked levels with RSD between 2.1 and 11.3%. These results indicated that the method has potential for enrichment and detection of trace levels of SAL residual in animal food products.

Diethylenetriamine assisted functionalization of boronic acid on poly GMA-MAA-DVB for selective enrichment of glycoproteins and glycopeptides.

Cis-diol compounds are class of biomolecules including nucleosides, glycoproteins, saccharides, and nucleotides, which play vital roles in various biological processes. Due to low abundances of these species in the complex biological samples, their identification and analysis is difficult. Boronate affinity materials are commonly used for the isolation and enrichment of cis-diol compounds, due to their unique, facile and selective enrichment mechanism. In this study we report a selective approach to extract nucleosides, glycopeptides and glycoproteins using boronic acid functionalized GMA-MAA-DVB polymer. This novel polymer, reported for the first time in proteomics, have high BET surface area (132.8447 m2 g-1) which contribute to efficient enrichment and average pore size (20.3449 nm) to facilitates the nano confinement effect for strong interactions. Hydrophilic character of methacrylic acid and diethylenetriamine, along with inherent affinity of boronic acid for glycosylated biomolecules result in selectivity up to 1:500 for peptides and 1:1000 for glycoprotein. Binding constant for cis-diol compounds are in the range of 10-4 to 10-6 M and theoretical binding capacity up to 85 mg g-1 for HRP and 180 mg g-1 for IgG, respectively. Furthermore, boronic acid functionalized polymer (BFP) enrich glycoproteins and glycopeptides in range of 1 pg mL-1 and 0.04 ng mL-1 with S/N ≥ 3. Finally, material is applied to enrich the glycoproteins from healthy human saliva sample and six glycoproteins are identified.

[Preparation of novel phenyl boronic acid functionalized silica gel using triazo-cyanide click chemistry and its application in glycoprotein/glycopeptide selective enrichment].

The application of boronic acid affinity chromatography to glycoprotein/glycopeptide enrichment is increasingly maturing. The enrichment selectivity, biocompatibility, and facile operation protocol are key aspects in efficient enrichment methods. In this work, a novel triazo-cyanide boronic acid functionalized material (TCNBA) was prepared using triazo-cyanide click chemistry. The TCNBA was proved to be successfully synthesized through infrared ray (IR) characterization. Subsequently, the glycopeptide/glycoprotein enrichment selectivity of the TCNBA was evaluated. Matrix-assisted laser desorption/ionization time-of-flight mass (MALDI-TOF MS) was employed for the glycopeptide enrichment selectivity evaluation. Taking the digestion of horseradish peroxidase (HRP) and immunoglobulin G (IgG) as samples, 13 and 11 glycopeptides could be characterized with improved signals after TCNBA enrichment, respectively. High abundance non-glycopeptides could be removed effectively from the eluting fraction. This result indicates the high glycopeptide enrichment selectivity of TCNBA. In addition, a mixture of HRP and bovine serum albumin (BSA) enzymatic solution (1:10, amount of substance ratio) was utilized as a sample, and five glycopeptide signals could be identified following enrichment. To evaluate the glycoprotein enrichment selectivity, sodium salt-polyacrylamide gel electrophoresis (SDS-PAGE) was adopted as an evaluation method. Mixtures of HRP, IgG, BSA, and ribonuclease B (RNaseB) proteins were employed as samples, and the results demonstrated that TCNBA had a high glycoprotein enrichment selectivity. The application of TCNBA to the analysis of a real biosample was also evaluated using human plasma. The results indicated the TCNBA could be utilized in large-scale glycoprotein analysis.

Highly Efficient Separation of Glycoprotein by Dual-Functional Magnetic Metal-Organic Framework with Hydrophilicity and Boronic Acid Affinity.

Protein glycosylation plays a critical role in post-translational modifications of proteins in the organism and is involved in many diseases. However, the huge challenge for glycoproteins to be highly specific isolated and adsorbed from complicated biological samples results from their low abundance and interference. In this work, a novel dual-functionalized magnetic metal-organic frameworks nanoparticle for selective enrichment of glycoproteins was synthesized for the first time. Due to the abundant amino groups and grafted phenylboronic acid, the proposed nanoparticles have the dual properties of hydrophilicity and boronic acid affinity. The obtained nanoparticles show high binding capacities toward glycoproteins under physiological state (pH 7.4) such as ovalbumin (327.28 mg/g), transferrin (241.17 mg/g), horseradish peroxidase (530.79 mg/g). Furthermore, the nanoparticles still have excellent enrichment performance after being used six times repeatedly. More importantly, the prepared nanoparticles also have great potential applications in the adsorption of glycoproteins from complex biological specimens.