Detection and adsorption of 2-methyl-4-chlorophenoxyacetic acid in vegetables via dual-functional molecularly imprinted polymer doping with carbon dot.

2-Methyl-4-chlorophenoxyacetic acid (MCPA) is one of the most widely used herbicides, so adsorption and detection of MCPA in the environment is critical. Blue fluorescent carbon dot (CD) was synthesized from citric acid and urea, which could be quenched by MCPA. Herein, bifunctional molecularly imprinted polymer (CD@MIP) was prepared on monodisperse poly (glycidyl methacrylate-co-ethylene glycol dimethacrylate) microspheres, with 4-vinylpyridine as the functional monomer, ethylene glycol dimethacrylate as the cross-linking agent, and doped with CD. The enrichment ability of CD@MIP for MCPA and fluorescence detection performance were determined. The maximum adsorption amount of MCPA was 93.9 mg g-1 as determined by isothermal adsorption experiments and was in accordance with the Langmuir adsorption model. The results of the kinetic experiments showed that the adsorption equilibrium reached within 30 min, which possessed a relatively fast adsorption rate and was in accordance with the pseudo-second-order adsorption model. Both MIP without CD and non-imprinted polymers were also fabricated and tested as references. Fluorescence experiments showed good linearity of CD@MIP in the range of 0-80 µmol. The cabbage samples were analyzed by high performance liquid chromatography with a linear range of 0.02-15 µg mL-1, recoveries of 90.5%-98% and low relative standard deviations (RSD, n = 3) of 1.5%-5.9%. CD@MIP with excellent performance provides a feasible practical application in the detection and enrichment of MCPA.

Selective adsorption and identification of penicillin G sodium in milk by molecularly imprinted polymer doped carbon dot.

A carbon dot (CD) was prepared by o-phenylenediamine and water, which showed bright yellow fluorescence under ultraviolet light irradiation (λ = 580 nm), and verified good fluorescence quenching effect on penicillin G sodium (Png-Na). Using methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a crosslinker, and Png-Na as a template, a kind of composite microsphere combining CD and molecularly imprinted polymer (MIP) was synthesized by surface-initiated atomic transfer radical polymerization (SI-ATRP). For reasons of comparison, we also prepared MIP without CD and non-imprinted polymers (NIPs). Through static and dynamic adsorption experiments, the maximum adsorption capacity was 47.05 mg g-1 and the equilibrium time was 30 min. High-performance liquid chromatography (HPLC) was utilized to determine the content of Png-Na in the spiked milk samples. A sensitive, rapid, and simple method for determination of Png-Na in food samples was developed. The utilized approach enabled the quantification of Png-Na within the concentration range 20-1000 µg L-1 (with a limit of detection of 5 µg L-1). The recoveries achieved were in the range 93.3-98.2%, with a relative standard deviation of 1.2-4.2%. The results demonstrated that CD@MIP possessed the capability of specific adsorption and fluorescence detection of Png-Na, enabling simultaneous detection and enrichment of Png-Na in real samples.

Bifunctional fluorescent molecularly imprinted resin based on carbon dot for selective detection and enrichment of 2,4-dichlorophenoxyacetic acid in lettuce.

The work provided a method for synthesizing a simple fluorescent molecularly imprinted polymer by surface-initiated atom transfer radical polymerization (SI-ATRP) and its application in real sample. Poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) microspheres were selected as a matrix, 4-vinylpyridine, ethylene glycol dimethacrylate, 2,4-dichlorophenoxyacetic acid (2,4-D) as functional monomer, cross-linker and template molecule, respectively, to fabricate MAR@MIP with core-shell structure. For comparison, carbon dot (CD) as a fluorescence source was synthesized with o-phenylenediamine and tryptophan as precursors via hydrothermal method and integrated into MIP to acquire MAR@CD-MIP. MAR@CD-NIP was also prepared without adding the template molecule. The adsorption capacity of MAR@CD-MIP reached 104 mg g-1 for 2,4-D, which was higher than that of MAR@MIP (60 mg g-1). However, the adsorption capacity of MAR@CD-NIP was only 13.2 mg g-1. The linear range of fluorescence detection for 2,4-D was 18-72 µmol/L, and the limit of detection (LOD) was 0.35 µmol/L. The fluorescent MAR@CD-MIP was successfully applied in enrichment of lettuce samples. The recoveries of the three spiked concentrations of 2,4-D in lettuce were tested by fluorescence spectrophotometry and ranged in 97.3-101.7 %. Meanwhile, the results were also verified by HPLC. As a result, bi-functional molecularly imprinted resin was successfully fabricated to detect and enrich 2,4-D in real samples, and exhibited good selectivity, sensitivity and great application prospect in food detection.

Biobased Tannic Acid-Chitosan Composite Membranes as Reusable Adsorbents for Effective Enrichment of Phosphopeptides.

High-performance reusable materials from renewable resources are rare and urgently required in bioseparation. Herein, a series of tannic acid-chitosan composite membranes for the enrichment of phosphopeptides were fabricated by the freeze casting method. First, a tannic acid-chitosan composite membrane was acquired via the multiple hydrogen bonds between tannic acid and chitosan, which had a long-range aligned three-dimensional microstructure. Second, a covalent-hydrogen bond hybrid composite was also fabricated, with stable and aligned honeycomb-like microstructures that formed by the synergy of covalence and hydrogen bonding. Besides, a ternary composite membrane was "one-pot" synthesized by the copolymerization of tannic acid, chitosan, and Ti4+ ions, indicating the feasibility of involving metal ions in the composition of the polymer skeleton in place of additional modification steps. The as-prepared chitosan composite membranes exhibited excellent performance in the enrichment of phosphopeptides from ß-casein tryptic digest and human serum. Benefitting from the long-range aligned honeycomb-like structure coordinated by hydrogen bonds and covalent bonds, and a large number of pyrogallol functional groups provided by tannic acid, the covalent-hydrogen bond hybrid membrane showed excellent reusability and could be reused up to 16 times in phosphopeptide enrichment, as far as we know, which is the best reported result to date.

Simple fabrication of carbon quantum dots and activated carbon from waste wolfberry stems for detection and adsorption of copper ion.

Removal of heavy metal pollution is an endless topic, because heavy metals can cause irreversible damage to the human body and environment. It is urgent to develop novel materials for detection and adsorption of heavy metal ions. In this paper, waste wolfberry straw was utilized as a carbon source, and two simple methods were developed to successfully prepare activated carbon (AC) and carbon quantum dots (CQDs). The fabrication conditions were optimized by adjusting the mass ratio of precursor to activator, type of activator and activation times. When sodium hydroxide (NaOH) was selected as an activator (6 : 1, mass ratio of NaOH to AC-precursor), and the activation was performed at 600 °C for 1 h, the highest specific surface area of the obtained AC-NaOH-3 reached 3016 m2 g-1. The adsorption capacity for copper ions (Cu2+) reached 68.06 mg g-1. The preparation conditions for CQDs were also optimized by adjusting the concentration of wolfberry stem, reaction time and temperature. When the wolfberry stem concentration was 7.5 g L-1, and the activation was performed at 200 °C for 24 h, the obtained CQDs exhibited strong fluorescence emission in the blank and 12 kinds of metal ion solutions, respectively, however, the fluorescence intensity was remarkably decreased after adding Cu2+. In the range of 10-80 nM, the linear correlation coefficient between the concentration of Cu2+ and fluorescence intensity of CQDs was 0.992, and the limit of detection was 2.83 nmol L-1. Thus, these two kinds of materials were prepared from wolfberry stem, which opened up a new way for the application in adsorption and detection of copper ions.

Ganoderma lucidum bran-derived blue-emissive and green-emissive carbon dots for detection of copper ions.

Ganoderma lucidum bran (GB) has a broad application prospect in the preparation of activated carbon, livestock feed, and biogas, but the preparation of carbon dots (CDs) from GB has never been reported. In this work, GB was applied as a carbon source and nitrogen source to prepare both blue fluorescent CDs (BCDs) and green fluorescent CDs (GCDs). The former were prepared at 160 °C for 4 h by a hydrothermal approach, while the latter were acquired at 25 °C for 24 h by chemical oxidation. Two kinds of as-synthesized CDs exhibited unique excitation-dependent fluorescence behavior and high fluorescent chemical stability. Based on the fantastic optical behavior of the CDs, they were utilized as probes for fluorescent determination of copper ions (Cu2+). In the range of 1-10 µmol L-1, the fluorescent intensity of BCDs and GCDs decreased linearly with the increase of Cu2+ concentration; the linear correlation coefficient reached 0.9951 and 0.9982, and the limit of detection (LOD) was 0.74 and 1.08 µmol L-1, respectively. In addition, these CDs remained stable in 0.001-0.1 mmol L-1 salt solutions; BCDs were more stable in the neutral pH range, but GCDs were more stable in neutral to alkaline conditions. The CDs prepared from GB are not only simple and low-cost, but also can realize the comprehensive utilization of biomass.

Adsorption of heavy metal onto biomass-derived activated carbon: review.

Due to the rapid development of the social economy and the massive increase in population, human beings continue to undertake processing, and commercial manufacturing activities of heavy metals, which has caused serious damage to the environment and human health. Heavy metals lead to serious environmental problems such as soil contamination and water pollution. Human health and the living environment are closely affected by the handling of heavy metals. Researchers must find several simple, economical and practical methods to adsorb heavy metals. Adsorption technology has been recognized as an efficient and economic strategy, exhibiting the advantages of recovering and reusing adsorbents. Biomass-derived activated carbon adsorbents offer large adjustable specific surface area, hierarchically porous structure, strong adsorption capacity, and excellent high economic applicability. This paper focuses on reviewing the preparation methods of biomass-derived activated carbon in the past five years. The application of representative biomass-derived activated carbon in the adsorption of heavy metals preferentially was described to optimize the critical parameters of the activation type of samples and process conditions. The key factors of the adsorbent, the physicochemical properties of the heavy metals, and the adsorption conditions affecting the adsorption of heavy metals are highlighted. In addition, the challenges faced by biomass-derived activated carbon are also discussed.

A combination of surface-initiated atom transfer radical polymerization and photo-initiated "thiol-ene" click chemistry: Fabrication of functionalized macroporous adsorption resins for enrichment of glycopeptides.

A hydrophilic adsorbent (Cys@poly(AMA)@MAR) was successfully prepared for the enrichment of N-glycopeptides via surface-initiated atom transfer radical polymerization (SI-ATRP) and photo-initiated "thiol-ene" reaction using monodisperse macroporous adsorbent resin (MAR) as adsorption matrix. Due to the presence of electron-deficient acrylic groups and electron-rich vinyl groups in allyl methacrylate (AMA), both of them can participate in free radical reaction. Therefore, the polymerization time of SI-ATRP was optimized. The resulting poly(AMA)@MAR was modified with l-cysteine (L-Cys) via photo-initiated "thiol-ene" reaction, and the amount of vinyl retained was determined by measuring the adsorption of Cu2+. The Cys@poly(AMA)@MAR pendant brushes with high density of amine and carboxyl groups could capture N-glycopeptides from IgG digest and human serum digest by hydrophilic interaction. The 22 N-glycopeptides were identified from IgG digest and the limit of detection reached 10 fmol. The 319 N-glycosylation sites and 583 N-glycopeptides were identified from 2 µL human serum digest and mapped to 147 glycoproteins. It demonstrates great potential and commercialization prospects for the enrichment of N-glycopeptides.

Preparation of Ganoderma Lucidum Bran-Based Biological Activated Carbon for Dual-Functional Adsorption and Detection of Copper Ions.

In this paper, Ganoderma lucidum bran was explored as the precursor to fabricate biomass activated carbon. When potassium hydroxide was selected as an activator (1:6, mass ratio of AC-12 to potassium hydroxide), and the activation condition was 700 °C at 5 h, the highest specific surface area reached 3147 m2 g-1. Carbon dots were prepared with citric acid monohydrate and thiourea as precursors and then loaded onto the surface of activated carbon by a simple and green method. Activated carbon for dual-functional had a high adsorption capacity. Additionally, based on its unique optical properties, the fluorescence response for detecting copper ion was established. The fluorescence intensity of the materials decreased linearly with the increase of copper ion concentration, in the range of 10-50 nmol L-1. The research opened up a new way for applying biomass activated carbon in the field of adsorption and detection. Highlights: (1) Carbon dots were loaded on the surface of activated carbon; (2) the simultaneous adsorption and detection were realized; (3) it provides a way for the preparation of dual-functional materials.

Facile Fabrication of Monodisperse Micron-Sized Dual Janus Silica Particles with Asymmetric Morphology and Chemical Environment.

Janus particles are a kind of materials with asymmetric morphology or surface chemical environment. But so far, the preparation of particles with dual asymmetry is still a challenging problem. Hence the cation surfactant hexadecyl trimethyl ammonium bromide and co-surfactant octadecylamine are applied to improve the Pickering emulsion stability, and the micron-sized silica particles are arranged in a single layer at the toluene-water interface through electrostatic interaction. Furthermore, organosilane reagents are added in the preparation process, resulting in the construction of asymmetric hydrophilic or hydrophobic mesoporous precisely onto the micron-sized silica particles surface. The cation surfactant-assisted Pickering emulsion method is simple, effective, and convenience, which can be applied in the synthesis of various dual Janus silica particles for specific applications.

Monodisperse Ti4+-immobilized macroporous adsorbent resins with polymer brush for improved multi-phosphopeptides enrichment in milk.

Enrichment of phosphopeptides before mass spectrometry (MS) analysis is essential due to the limitations of low abundance and poor ionization efficiency in complex biological samples. Immobilized metal affinity chromatography (IMAC), especially titanium ion (Ti4+)-IMAC, has become a popular strategy for enrichment of phosphopeptides due to high selectivity and sensitivity. Conventional Ti4+-immobilized macroporous adsorption resin (MAR) fabricated by monolayer modification can preferentially capture mono-phosphopeptide over multi-phosphopeptides, which takes on more functions in the regulation of cell behaviors of organism. In this paper, a kind of monodisperse MAR microsphere with functional polymer brush (Ti4+-Brush@MAR) was prepared and modified via surface-initiated atom transfer radical polymerization (SI-ATRP). Compared with common Ti4+-MAR without polymer brush, Ti4+-Brush@MAR exhibited high enrichment specificity not only for mono-phosphopeptides but also for multi-phosphopeptides in ß-casein or milk digest samples. As a result, a total of 93 unique phosphopeptides mapped to 18 phosphoproteins were identified from 5 µL milk, and the limit of detection is 10 fmol. It is expected that Ti4+-Brush@MAR would be utilized to enrich both multi-phosphopeptides and mono-phosphopeptides in additional biological or food samples.

Carbon dot-functionalized macroporous adsorption resin for bifunctional ultra-sensitive detection and fast removal of iron(III) ions.

Heavy metal pollution has spread around the world with the development of industry, posing a major threat to human health. It is urgent to design and fabricate bifunctional materials for detection and adsorption of heavy metal ions. Herein, poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) microspheres, a kind of common macroporous adsorption resin (MAR), were employed as the matrix, and carbon dots (CDs) with excellent optical properties were grafted onto the surface of MAR by surface-initiated atom transfer radical polymerization (SI-ATRP) and photo-initiated "thiol-yne" click chemistry. The synthesized MAR@poly(PA)@CD could produce fluorescence quenching with Fe3+. A simple fluorescence spectrometric method for detection of Fe3+ was established. The fluorescence intensity of MAR@poly(PA)@CD decreased linearly with the concentration of Fe3+ in the range of 0-70 nmol L-1, with a limit of detection (LOD) of 6.6 nmol L-1, which had the potential for trace detection. In addition, after SI-ATRP modification, many adsorption sites were generated on the surface of MAR, and the adsorption capacity for Fe3+ was 23.8 mg g-1. Isothermal and kinetic adsorption experiments were more consistent with the Langmuir model (r = 0.9992) and pseudo-second-order model (r = 0.9902), indicating that the adsorption was monolayer adsorption and chemical adsorption, respectively. MAR@poly(PA)@CD with dual functions of detecting and adsorbing Fe3+ was successfully prepared, showing great application prospects in the environmental field.

Fabrication of hydrophilic titanium (IV)-immobilized polydispersed microspheres via inverse suspension polymerization for enrichment of phosphopeptides in milk.

It is prerequisite to efficient extraction of phosphopeptides in bottom-up strategy for protein phosphorylation research. A kind of Ti4+-immobilized polydispersed phosphate-rich microsphere was fabricated via inverse suspension polymerization by employing vinylphosphonic acid (VPA) and N,N-methylenebisacrylamide (MBA) as functional monomer and crosslinker, respectively. The resulting microsphere demonstrated excellent sensitivity (as low as 10 fmol), selectivity (the mass ratio of ß-casein to BSA digests is 1/500), and adsorption capacity (up to 200 mg g-1). What's more, 113 unique phosphopeptides assigned to 25 unique phosphoproteins were indiscriminately identified from 5 µL of pasteurized milk digest, exhibiting great performance in capturing phosphopeptides. In this approach, only two steps were required to synthesize Ti4+-IMAC (Ti4+-Immobilized metal affinity chromatography). Compared with other methods required multistep modifying process, this strategy is simple and time-saving, offering a prospect of pilot production and commercialization. It is expected that the application of IMAC in milk and other food samples will still make it possible to unravel the huge complexity of the Foodome in the near future.

One-step fabrication of nitrogen-rich linear porous organic polymer-based micron-sized sphere for selective enrichment of glycopeptides.

In this work, nitrogen-rich linear porous organic polymers (POPs) were designed to improve glycopeptides enrichment efficiency in HILIC. Two kinds of novel POPs (CH-pPAL and CH-mPAL) were one-step prepared via the Schiff-base condensation reaction and intermolecular hydrogen-bonded using a flexible amine monomer (carbohydrazide, CH) to react with two aldehyde monomers, p-phthalaldehyde (pPAL) and m-phthalaldehyde (mPAL), respectively. The specific surface area of CH-pPAL and CH-mPAL was 238 and 232 m2 g-1, respectively. Based on the hydrogen-bond interaction, several narrow peaks existed in the PXRD patterns. Particularly, micron-sized spherical CH-pPAL possessed a honeycomb-like orderly tunnel structure. The contact angle of CH-pPAL and CH-mPAL severally was 35.4° and 28.8°, respectively, indicating excellent hydrophilicity of as-synthesized POPs. They both demonstrated high sensitivity and high adsorption capacity in glycopeptides enrichment. The 851 and 794 unique glycopeptides derived from 170 and 200 N-glycosylated proteins were identified after the enrichment by CH-pPAL and CH-mPAL within three independent replicates of proteins extracted from human serum, respectively. Therefore, these CH-based hydrophilic POP materials would be applied in the enrichment and identification of low-abundance N-linked glycopeptides from complicated biological samples.

Interface-Engineered Hollow Nanospheres with Titanium(IV) Binding Sites and Microwindows as Affinity Probes for Ultrafast and Enhanced Phosphopeptides Enrichment.

Enrichment and identification of phosphopeptides in real biological samples are of great significance in many aspects. Herein, Ti4+-immobilized silica hollow nanospheres were tailored via chelating with phosphonic acid groups produced from dealkylation of phosphonate ester functionalized silica hollow nanospheres, which were synthesized through a single micelle templated method with diethylphosphatoethyltriethoxysilane (DPTES) and tetramethoxysilane (TMOS) as silane precursors under neutral conditions. The characterization results of transmission electron microscopy (TEM), nitrogen sorption isotherms, FT-IR, and energy-dispersive X-ray (EDX) spectroscopy confirmed the successful preparation of Ti4+-immobilized silica hollow nanospheres (SHS-Ti; approximately 17 nm particle size), which possessed a 10 nm hollow cavity with 1.6 nm micropores on the thin shell (about 3.5 nm). Attributed to the immobilized Ti4+ and high specific area (396 m2/g), SHS-Ti was applied as a Ti4+-immobilized metal affinity chromatography (Ti-IMAC) material and showed good specificity, a low limit of detection (5 fmol), high selectivity (tryptic digestion mixture of bovine serum albumin/ß-casein, 1000:1 molar ratio), high binding capacity (120 mg/g for pyridoxal 5'-phosphate), and a high binding constant (1.30 × 103 L/mg). Particularly, benefiting from the unique hollow structure with microwindows on the thin shell, a short transport path, and small mass transfer resistance, SHS-Ti exhibited excellent enrichment speed in which both phosphopeptide loading and elution could be completed in 1 min. The 5298 unique phosphopeptides from 1618 unique phosphoproteins were identified after enrichment by SHS-Ti from 100 µg Jurkat cell lysates within three independent replicates. The results showed that SHS-Ti could be utilized as a novel and promising enrichment probe for phosphopeptide characterization in MS-based phosphoproteomics and related fields.

Enantioseparation in high performance liquid chromatography: preparation and evaluation of a vancomycin-based chiral stationary phase via surface-initiated atom transfer radical polymerization.

A chromatographic technique based on a chiral stationary phase (CSP) has been explored for enantioseparation. Herein, poly(glycidyl methacrylate) (poly(GMA)) brushes were grafted on the surface of silica gel via surface-initiated atom transfer radical polymerization (SI-ATRP), followed by the introduction of vancomycin as a chiral selector. The as-synthesized material was characterized by elemental analysis, scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) and thermogravimetric analysis (TGA), proving the formation of vancomycin-immobilized brushes. Then the resulting CSP was explored to separate 7 racemic drugs (bicalutamide, 1-benzyl-5-phenylbarbituric acid, chlorpheniramine maleate, fluoxetine hydrochloride, verapamil hydrochloride, benzoxazocine hydrochloride and isoprenaline hydrochloride) in high performance liquid chromatography (HPLC). Several factors affecting the enantioseparation performance of the vancomycin-immobilized CSP, including the triethylamine (TEA) content in the buffer, pH value, content of organic solvent in the mobile phase, flow rate and injection volume, were mainly optimized. Under the optimal conditions, baseline separation of fluoxetine hydrochloride (RS = 2.52) was achieved, which was better than that on a commercial Chirobiotic V column, while enantioseparation of bicalutamide (RS = 1.01), chlorpheniramine maleate (RS = 0.77), 1-benzyl-5-phenylbarbituric acid (RS = 0.67), isoprenaline hydrochloride (RS = 0.73), verapamil hydrochloride (RS = 0.91) and benzoxazocine hydrochloride (RS = 1.03) was partly achieved. It was concluded that SI-ATRP is a robust way to fabricate vancomycin-based CSPs for enantioseparation.

Design and fabrication of reusable core-shell composite microspheres based on nanodiamond for selective enrichment of phosphopeptides.

A kind of core-shell composite microsphere (CM) with nano-on-micro structure was synthesized via grafting amine-modified nanodiamonds onto the surface of monodisperse nonporous polymeric microsphere. In this way, the agglomeration of nanodiamond particles in the solution was avoided. After modification with pyrogallol groups, CM could chelate titanium ions (Ti4+) and thus be utilized as immobilized metal affinity chromatography (IMAC) sorbent to enrich phosphopeptides from biological samples. The resulting Ti4+-CM exhibited high enrichment efficiency and specificity to phosphopeptides. A total of 106 of unique phosphopeptides mapped to 29 phosphoproteins were clearly identified from 5 µL of a milk digest after enrichment. Owing to the strong chelation between Ti4+ and pyrogallol ligands, the Ti4+ is not released from the sorbent after completion of the enrichment process. As a result, the Ti4+-CM sorbent could be reused, and no significant loss of enrichment efficiency occurred even on the fourth run employing a ß-casein digest as the sample. The strategy adopted presents a new way to prepare a high-performance reusable IMAC sorbent.

Progress of molecular imprinting technique for enantioseparation of chiral drugs in recent ten years.

The existence of chiral compounds is a very common phenomenon in the field of medicine, and nearly 60% of drugs are chiral. The separation of racemic drugs is the key to safe use of drugs. Molecularly imprinted technique (MIT) has attracted wide attention in the separation of chiral drugs in recent years due to its simple operation and strong specific recognition ability of target molecules. Molecularly imprinted polymers (MIPs) have been used as selective adsorbents in a variety of analytical techniques, and excellent progress has been made in the separation of chiral drugs. In this paper, the MIT for the separation of drug in recent ten years is reviewed. We will introduce how to achieve chiral drug resolution in different chromatographic techniques based on the morphological differences of MIPs (micron-sized particles, nanoparticles and monolithic column materials) as the classification criteria. Furthermore, the contributions of surface molecularly imprinted technique (SMIT) and molecularly imprinted membrane (MIM) technology in racemic drug resolution are also introduced. Finally, the main application challenges of chiral MIT are briefly introduced, and the future development direction of this field is prospected.

Preparation of core-shell microporous organic polymer-coated silica microspheres for chromatographic separation and N-glycopeptides enrichment.

Through a "one-pot" strategy, a layer of microporous organic polymer was coated onto the surface of monodisperse amino-functionalized silica microsphere via amino-aldehyde condensation reaction with core-shell structure. The change in chemical structure of material before and after modification was determined by Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy. Due to existence of a large number of amino and aldehyde groups in microporous organic polymer shell, the water contact angle decreased from 56.8° (silica microspheres) to 34.7° (microporous organic polymer-coated silica microspheres). Based on these properties, microporous organic polymer-coated silica microspheres were employed as the stationary phase for capillary liquid chromatography and successfully offered baseline separation of polar small molecules. Additionally, the material could also be served as the sorbent of hydrophilic interaction chromatography to enrich glycopeptides from human serum digest. A total of 470 unique N-glycopeptides and 342 N-glycosylation sites mapped to 112 N-glycosylated proteins were unambiguously identified from 2 µL of human serum, exhibiting a promising application prospect of microporous organic polymer-coated silica microspheres in the pretreatment of proteomics samples.

Facile "one-pot" preparation of phosphonate functional polythiophene based microsphere via Friedel-Crafts reaction for selective enrichment of phosphopeptides from milk.

A novel kind of phosphonate functionalized polythiophene microsphere was designed and fabricated via Friedel-Crafts reaction. Diethyl (thiophen-2-ylmethyl) phosphonate (DTYP) and thiophene were co-polymerized by Fe (III) catalysis, without any surfactant, stabilizer and initiator. Functional phosphonate group was directly introduced into the microsphere without redundant modification steps. The adsorption amount of the as-synthesized microsphere, Ti-poly(Th-co-DTYP), was as high as 66.7 mg/g, which was higher than that of commercial Ti4+-IMAC microsphere (49.7 mg/g). The microsphere was explored on the specific capture of phosphopeptides from either tryptic digests of milk or HeLa cell protein. As a result, 88 of unique phosphopeptides mapping to 21 phosphoproteins were identified from 150 µg of milk tryptic digest after enrichment, and a total of 2534 unique phosphopeptides mapping to 1087 phosphoproteins was identified from HeLa cell. It is expected that such a robust and facile approach will be explored in other functional microspheres to be commercialized in the future.