A polyvinyl alcohol-coated silica gel stationary phase for hydrophilic interaction chromatography.

Multiple layers of polyvinyl alcohol (PVA) coating are generated onto silica gel by thermal immobilization to form a stationary phase applied for hydrophilic interaction liquid chromatography (HILIC). It offers an easy way to manipulate the thickness of PVA coating and the obtained stationary phase demonstrated high efficiency and high chemical stability.

Facile preparation of polyvinyl alcohol coated SiO2 stationary phases for high performance liquid chromatography.

A facile method to prepare a polar stationary phase for hydrophilic interaction chromatography (HILIC) was proposed by coating polyvinyl alcohol onto silica particles (PVA-Sil). A water or organic solvent-insoluble permanent PVA coating on the silica particle surface can be formed simply by dipping silica particles into a hot PVA solution and then settled from this solution, leaving a thin layer of PVA coating and frozen in a freezer. The PVA-Sil shields the silica core from solution erosion to some degree and the pH tolerance range was extended to 9.5 from 8.0 for bare silica. PVA-Sil demonstrated a good hydrophilic property for several kinds of polar compounds and ∼57000 m(-1) of plate count was achieved. This method can also be extended as a universal method to prepare various stationary phases with exchangeable functionalities by doping the desired ingredient in a PVA solution.

Design of green coating material of combining rigid and flexible properties for the extraction of aminoglycosides residues.

Bio-based and low-cost hybrid polyvinyl alcohol (PVA) and gelatin (Gel) hydrophilic macromolecular complex coated microspheres were prepared based on one-pot process, characterized, and applied as novel sorbent materials for the purification of trace aminoglycosides from complex matrices. PVA acts as a "rigid" component in the hybrid complex to enhance its mechanical properties, while Gel's "flexible" role is to improve the swelling properties of the hybrid complex in water. It is shown that hybrid PVA/Gel-functionalized sorbents are more efficient than the respective PVA or Gel sorbents since the presence of Gel increases the material selectivity for aminoglycosides, which is due to the specific interactions occurring between the targets and amino acid residues in the hybrid materials. Under the optimum conditions, material preparation and pretreatment processes were entirely carried out in single water system without toxic organic solvent. The detection limit (LOD) of spectinomycin, kanamycin, streptomycin and dihydrostreptomycin in honey were 0.811, 0.303, 0.168, 0.045 µg⋅kg-1 respectively. Linearity was obtained in the range of 20 to 2000 ug⋅kg-1, relative recovery yield up to 84.1-111.7% were obtained and matrix effect of all four aminoglycosides was within 100.8-107.6%. Intra-day and inter-day precision under four spiking levels (5, 200, 500 and 1000 ug⋅kg-1) were less than 10.9% (n=6) and 13.6% (n=3) respectively. In addition, the sorbents exhibited excellent reusability even after six recycles. This work demonstrates the potential of bio-based and low-cost hybrid polymer extraction platforms as promising bonded phase alternatives, in which eco-friendly and natural-based polymers can be used to improve the material selectivity and are conducive to the realization of "green chemistry".

Application of core-satellite polydopamine-coated Fe3O4 nanoparticles-hollow porous molecularly imprinted polymer combined with HPLC-MS/MS for the quantification of macrolide antibiotics.

Core-satellite-structured magnetic nanosorbents (MNs) used for the selective extraction of macrolide antibiotics (MACs) were prepared in this study. The MNs (core-satellite polydopamine-coated Fe3O4 nanoparticles-hollow porous molecularly imprinted polymer) consisted of polydopamine-coated Fe3O4 nanoparticles (Fe3O4@PDA) "core" linked to numerous hollow porous molecularly imprinted polymer (HPMIP) "satellites" with bridging amine functional groups. It is worth mentioning that HPMIPs act as "anchors" for selectively capturing target molecules. Polymers were characterized using TEM, SEM, FT-IR, VSM, and TGA and applied as magnetic dispersive solid-phase extraction (MDSPE) sorbents for the enrichment of trace MACs from a complex food matrix prior to quantification by HPLC-MS/MS. Nanocomposites revealed outstanding magnetic properties (36.1 emu g-1), a high adsorption capacity (103.6 µmol g-1), selectivity (IF = 3.2), and fast kinetic binding (20 min) for MACs. The multiple advantages of the novel core-satellite-structured magnetic molecularly imprinted nanosorbents were confirmed, which makes us believe that the preparation method of the core-satellite MNs can be applied to other fields involving molecular imprinting technology.

A polyvinyl alcohol-coated core-shell magnetic nanoparticle for the extraction of aminoglycoside antibiotics residues from honey samples.

The authors describe magnetic nanoparticles comprising of a Fe3O4 core and a polyvinyl alcohol (PVA) coating for use in dispersive solid phase extraction (DSPE) of aminoglycoside antibiotics (AAs). The sorbent was investigated by Transmission electron microscope (TEM), Fourier transform infrared spectrometer (FT-IR), thermo-gravimetric analysis (TGA), nitrogen adsorption-desorption isotherms and so on. The extraction conditions consisting of the proportion of ACN, pH value, buffer concentration and sorbent dosage were optimized. The nanoparticles have a large surface area (73.28 m2 g-1), a high binding capacity (11.33 µmol g-1) and a fast binding time (30 s). The Fe3O4@PVA is shown to be an effective adsorbent for the enrichment of AAs (streptomycin, dihydrostreptomycin and kanamycin) in spiked honey. The limits of detection are as low as 0.993, 0.913 and 1.23 µg kg-1 for streptomycin, dihydrostreptomycin and kanamycin, respectively. The recoveries varied from 82.9% to 100.7% at the three spiking levels tested (40, 400, 4000 µg⋅kg-1). Intra-day and inter-day assay precision were < 12.1% (n = 6) and <12.8% (n = 3) at three spiking levels. These data showed that the method could be applied to the extraction of AAs in honey samples.

A polyvinyl alcohol-functionalized sorbent for extraction and determination of aminoglycoside antibiotics in honey.

A novel highly hydrophilic sorbent simply prepared by coating polyvinyl alcohol (PVA) onto silica gel was used for extraction and determination of aminoglycoside antibiotics (AAs). The fabricated PVA coating is aimed to effectively protect core silica gel inside and offers good hydrophilic property. In combination of hydrophilic interaction chromatography tandem mass spectrometry, the performance of the sorbent was evaluated by selecting four model AAs (dihydrostreptomycin, streptomycin, kanamycin, spectinomycin). The sorbent was found to have effective adsorption ability to hydrophilic AAs, which was superior or comparable to those of commercial ones. Good recoveries (84-112%) of model AAs spiked in honey were obtained with good precision (<12.4%) and the limit of quantitation for the proposed method was in the range of 7.8-19.4ng/mL.

Synthesis of molecularly imprinted polymer sorbents and application for the determination of aminoglycosides antibiotics in honey.

Aminoglycoside antibiotic (AA)-selective molecularly imprinted polymer (MIP) sorbent was synthesized by polymerization of methacrylic acid and ethylene glycol dimethacrylate in the presence of streptomycin as template molecule. The MIP sorbent was in detail characterized and its performance was evaluated by selecting four model AAs including streptomycin, gentamicin, spectinomycin and dihydrostreptomycin. Relative to non-imprinted polymer (NIP), the MIPs exhibited much higher recognizable capacity and specificity to the AAs and negligible adsorption for non-AAs as well. In combination of hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS), the MIP sorbent-based solid phase extraction (SPE) was able to effectively determine the residue of four model AAs in honey samples with recovery ranging from 90% to 110%. The limit of detection (and the limit of quantitation) of streptomycin, gentamicin, spectinomycin and dihydrostreptomycin was 4.5 (15.0), 2.4 (8.0), 6.0 (20.0) and 1.8 (6.0) µg/kg, respectively. Relative standard deviations of intraday and inter-day assay under three spiked levels were 4.4-12.0% and 6.8-14.6%, respectively.