Ratiometric detection of I- using a dysprosium-based metal-organic framework with a single emission center.

In this study, a dysprosium-based metal-organic framework (MOF) sensor (Dy-MOF) was developed for the ratiometric detection of I- in aqueous medium. Upon excitation at 230 nm, Dy-MOF shows two dominant emission bands at 464 nm and 574 nm assigned to (4F, 4D)5/2 → 6H9/2 + 6F11/2 and 4F9/2 → 6H13/2 transition of Dy3+, respectively, which have different sensitivities toward iodide ions. The introduction of I- slightly weakened the blue emission at 464 nm and significantly quenched the yellow emission at 574 nm. Thus, ratiometric sensing for iodide was realized using the yellow-to-blue intensity ratio of Dy3+. Dy-MOF exhibits superior sensing behavior towards I- with high selectivity, sensitivity and low detection limit (24 nM). This study also provides a strategy for the construction of a ratiometric sensor with dual-emission bands originating from only one emission center.

A ratiometric luminescence sensing platform based on lanthanide-based silica nanoparticles for selective and sensitive detection of Fe3+ and Cu2+ ions.

Detection of Fe(III) and Cu(II) in water is highly desirable because their abnormal levels can cause serious harm to human health and environmental safety. In this work, a ratiometric luminescence sensing platform based on lanthanide-based silica nanoparticles was constructed for the detection of Fe3+ and Cu2+ ions. The terbium-silica nanoparticles (named SiO2@Tb) with dual-emission signals were successfully prepared by grafting Tb3+ ions onto trimellitic anhydride (TMA) functionalized silica nanospheres. It can serve as a ratiometric fluorescent probe for the detection of Fe3+ and Cu2+ ions in water with the green emission of Tb3+ ions as a response signal and the blue emission of silica nanospheres as the reference signal. Significantly, an easy-to-differentiate color change for visual detection was also realized. SiO2@Tb shows high sensitivity even in very low concentration regions towards the sensing of Fe3+ and Cu2+ with low detection limits of 0.75 µM and 0.91 µM, respectively. Moreover, the mechanism for the luminescence quenching of SiO2@Tb was systematically investigated, and was attributed to the synergetic effect of the absorption competition quenching (ACQ) mechanism and cation exchange. This study demonstrates that SiO2@Tb can be employed as a promising fluorescent probe for the detection of Fe3+ and Cu2+ ions, and the combination of lanthanide ions with silica nanoparticles is an effective strategy to construct a ratiometric fluorescent sensing platform for the determination of analytes in environmental detection.

Single-Crystal-to-Single-Crystal Transformation of Two Copper(II) Metal-Organic Frameworks Modulated by Auxiliary Ligands.

The single-crystal-to-single-crystal (SCSC) transformations of metal-organic frameworks (MOFs) are fascinating because we can directly observe the change of the crystal structure during the transformation process. It also greatly helps to understand the delicate interaction between the guest molecules and the skeleton framework and therefore fosters a deep understanding of gas storage and separation within the frameworks. Herein, we report two novel MOFs, [Cu8(BCB)4(µ3-OH)2(µ3-O)(H2O)8(Py)5]·16DMF·52H2O (1) and [Cu3(BCB)2(Py)6]·DMF·11H2O (2) (Py = pyridine; DMF = N,N'-dimethylformamide), which were constructed through the self-assembly of Cu2+ and 4,4',4″-benzenetricarbonyltribenzoic acid (H3BCB) by a solvothermal reaction. Although the structure and coordination patterns of compound 1 are pretty different from those of 2, the two Cu-MOFs were prepared from identical ligands and similar reaction conditions. Interestingly, compound 1 will change to 2 wholly and gradually after the addition of a certain amount of Py with a small amount of dilute hydrochloric acid. This conversion represents a scarce example of SCSC transformation involving transition-metal-based MOFs. Moreover, with its microporous nature, compound 2 shows large carbon dioxide (CO2) uptake capability and good selectivity for CO2/N2 separation. Furthermore, both compounds 1 and 2 could be used as excellent heterogeneous catalysts toward the cyanosilylation reaction under solvent-free conditions.

An europium(III) metal-organic framework as a multi-responsive luminescent sensor for highly sensitive and selective detection of 4-nitrophenol and I- and Fe3+ ions in water.

A luminescence sensor based on an europium(III)-based lanthanide-organic framework, [Eu(BCB)(DMF)]·(DMF)1.5(H2O)2 (1), was synthesized via a solvothermal method using 4,4',4''-benzenetricarbonyltribenzoic acid (H3BCB) as a bridging ligand. Single-crystal X-ray diffraction indicates that Eu centers are eight-coordinated with a trigonal dodecahedron and a square antiprismatic configuration, and adjacent Eu atoms are bridged by BCB organic linkers to form a 3D rod-packing structure. Photoluminescence studies show that compound 1 emits bright red luminescence and behaves as a multi-responsive luminescent sensor toward 4-nitrophenol (4-NP) and I- and Fe3+ ions in water with high sensitivity, selectivity and low detection limits. Furthermore, the possible luminescence sensing mechanisms were also investigated by PXRD analysis, UV-vis spectroscopy and X-ray photoelectron spectroscopy (XPS). The recognition mechanism for 4-NP and I- ions can be attributed to the competition absorption and that for Fe3+ ions is considered to be a multi-quenching mechanism dominated by competition absorption. This study demonstrates that the lanthanide-based MOF might be a promising candidate for the detection of 4-NP and I- and Fe3+ ions in aqueous medium.

Discovery of natural 15-LOX small molecule inhibitors from Chinese herbal medicine using virtual Screening, biological evaluation and molecular dynamics studies.

Chinese herbal medicines (CHM) are frequently used to treat different types of inflammatory diseases and 15-Lipoxygenase (15-LOX) is a critical target enzyme for treating various inflammatory diseases. In this study, natural 15-LOX inhibitors were identified in CHM using an approach of virtual screening combined with the biological assays. First, an in-house Chinese medicine database containing 360 compounds was screened using a virtual screening approach based on pharmacophore and molecular docking to uncover several novel potential 15-LOX inhibitors. Secondly, the inhibitory effect of virtual screening hits against the 15-LOX enzyme was validated in an in vitro enzyme inhibition assay. Then, a tumor necrosis factor-α (TNF-α) release assay was carried out to explore the anti-inflammatory response of the active compounds. Furthermore, molecular dynamics (MD) simulation and binding free energy calculation were applied to analyze the process of inhibitors binding and also compared the mode of binding of the inhibitors by using the Molecular Mechanics-Generalized Born Surface Area (MM/GBSA) method. Finally, licochalcone B and eriodictyol were confirmed as inhibitors of the 15-LOX enzyme with IC50 values of 9.67 and 18.99 µM, respectively. In vitro cell-based assay showed that licochalcone B and eriodictyol inhibited the release of TNF-α factor in RAW264.7 cells stimulated by lipopolysaccharides (LPS) in a dose-dependent manner. Molecular dynamics and binding free energy analysis showed that the two 15-LOX-ligand systems immediately attained equilibrium with almost 1 Å fluctuation, the calculated binding free energies were found around -18.89 and -12.96 kcal/mol for licochalcone B and eriodictyol, respectively. Thr412, Arg415, Val420, Thr429, Ile602 and Trp606 were the main amino acid residues for the inhibition of 15-LOX enzyme activity. The current study confirms that licochalcone B and eriodictyol are 15-LOX inhibitors and can suppress the release of the TNF-α factor in RAW264.7 cells stimulated by LPS, thus providing a basis for the follow-up research and development for 15-LOX inhibitors.

Nomogram to differentiate between aortic dissection and non-ST segment elevation acute coronary syndrome: a retrospective cohort study.

BACKGROUND: Aortic dissection (AD) and non-ST segment elevation acute coronary syndrome (ACS) are two of the most life-threatening diseases encountered in the emergency department (ED), but there are no rapid and reliable tools for differentiation. The purpose of this study is to develop and validate a nomogram that incorporates both the clinical characteristics and bedside laboratory tests available to differentiate between AD and non-ST segment elevation ACS (NSTE-ACS). METHODS: Between January 2016 and July 2018, patients with AD and NSTE-ACS were enrolled and divided into training and validation groups. The least absolute shrinkage and selection operator (LASSO) regression model was used to select the factors with significant value of predicting the diagnosis of AD. A nomogram was built on the basis of multivariable logistic regression analysis. Area under the curve (AUC) of receiver operating characteristic (ROC) curve and the calibration curve were used to assess the performance of the nomogram. Decision curve analysis was performed to assess the clinical utility of the nomogram. RESULTS: A final cohort of 263 patients (94 patients with AD and 169 patients with NSTE-ACS) were enrolled. Six variables were incorporated in the nomogram: pain severity, tearing pain, pulse asymmetry, electrocardiogram (ECG), D-dimer level and troponin I level. The AUC of the nomogram to predict the probability of AD was 0.919 (95% CI, 0.876-0.962) in the training group and 0.938 (95% CI, 0.888-0.989) in the validation group. The calibration curve demonstrated a good consistency between the actual clinical results and the predicted outcomes. The decision curve analysis indicated that the nomogram had higher overall net benefits in predicting AD in both the training group and the validation group. CONCLUSIONS: We developed and validated a predictive nomogram that could be used as a tool to differentiate AD from NSTE-ACS rapidly and accurately.

Clinical outcomes of left bundle branch pacing compared to right ventricular apical pacing in patients with atrioventricular block.

BACKGROUND: Left bundle branch pacing (LBBP) can produce near normalization of QRS duration. This has recently emerged as alternative technique to right ventricular pacing and His bundle pacing. HYPOTHESIS: The purpose of this study is to evaluate clinical outcomes of LBBP compared to right ventricular apical pacing (RVAP). METHODS: A total of 70 AVB patients with indications for ventricular pacing were retrospectively studied. LBBP was attempted in 33 patients, classified as LBBP group. The other patients were classified as RVAP group. Pacing parameters, electrocardiogram and echocardiogram characteristics, heart failure hospitalization (HFH), and atrial fibrillation (AF) were evaluated perioperatively and at follow-ups. Patients were followed in the device clinic for a minimum of 12 months and up to 24 months at a 3-6 monthly interval. RESULTS: LBBP was successful in 29 of 33(87.9%) patients while all 37 of the remaining patients successfully underwent RVAP. Paced QRS duration was significantly narrower in the LBBP group compare to RVAP(110.75 ± 6.77 ms vs. 154.29 ± 6.96 ms, p = .000) at implantation, and the difference persisted during follow-ups. Pacing thresholds (at implantation: 0.68 ± 0.22 V in the LBBP group and 0.73 ± 0.23 V in the RVAP group, p = .620) remained low and stable during follow-ups. The cardiac function in the LBBP group remained stable during follow-ups (LVEF%:55.08 ± 4.32 pre-operation and 54.17 ± 4.34 at the end of follow-up, p = .609), and better than RVAP group (LVEF%: 54.17 ± 4.34 vs. 50.14 ± 2.14, p = .005). Less HFH was observed in the LBBP group (2/29,6.89%) compared to RVAP group (10/37,27.03%). CONCLUSIONS: The present investigation demonstrates the safety and feasibility of LBBP that produces narrower paced QRS duration than RVAP. LBBP is associated with reduction in the occurrence of pacing-induced left ventricular dysfunction and HFH compared to RVAP in patients requiring permanent pacemakers.

A terbium(III) lanthanide-organic framework as a selective and sensitive iodide/bromide sensor in aqueous medium.

A potent luminescent sensor for the detection of iodide ions was developed based on a terbium(iii)-based lanthanide-organic framework [Tb(cpia)(H2O)2]n·nH2O (1), which was prepared under hydrothermal conditions using the 5-(4-carboxyphenoxy)isophthalic acid (H3cpia) bridging ligand. Compound 1 exhibits superior luminescence quenching behavior towards I- with high sensitivity and selectivity among various anions and shows real-time response. Moreover, the mechanism of the selective luminescence quenching response for I- can be mainly explained by the absorption competition between 1 and I-. According to this quenching mechanism, we find that compound 1 can also detect Br- by adjusting the excitation wavelength. Significantly, this work could serve as a general guidance for the design and synthesis of pollutant sensors.

Three new flavonoids from Penthorum chinense Pursh and their docking studies.

Three new flavonoids, pinocembrin-7-O-[3″-O-galloyl]-ß-D-glucose (1), pinocembrin-7-O-[2″-O-galloyl-4″,6″-hexahydroxydiphenoyl]-ß-D-glucose (2), 2',6'-dihydroxydihydrochalcone-4'-O-[2″-O-galloyl-4″,6″-hexahydroxydiphenoyl]-ß-D-glucopyranoside (3), and 12 known compounds (4-15) were isolated from Penthorum Chinense Pursh. The structures of all compounds were established mainly by NMR and MS experiments as well as the necessary chemical evidence. The anti-hyperlipidemic activities of the three new flavonoids were predicted by molecular docking.

Discovery of a natural PI3Kδ inhibitor through virtual screening and biological assay study.

Phosphoinositide-3-kinase-δ (PI3Kδ) is a key regulator in the process of IgE mediated mast cell degranulation, which directly induces allergic diseases, such as asthma. This study is aimed at discovery of natural PI3Kδ inhibitors from Chinese medicine and evaluating their anti-mast cell degranulation activity. A combined virtual screening based on 3D pharmacophore model and molecular docking was used to screen for bioactive ingredients directly targeting PI3Kδ. Then, an in vitro kinase inhibition assay was conducted to evaluate the PI3Kδ inhibitory activity of the virtual screening hits. Subsequently, a ß-hexosaminidase release assay was performed to verify the anti-mast cell degranulation activity of the active compounds. Finally, ginkgoneolic acid was identified as a PI3Kδ inhibitor (IC50 = 2.49 µM) and exhibited anti-mast cell degranulation activity in vitro (IC50 = 2.40 µM). Docking studies showed that Glu826, Val827 and Val828 were key amino acid residues for PI3Kδ inhibitory activity. Ginkgoneolic acid may be a potential lead compound for developing effective and safe PI3Kδ-inhibiting drugs.

Discovery of a Natural Syk Inhibitor from Chinese Medicine through a Docking-Based Virtual Screening and Biological Assay Study.

Spleen tyrosine kinase (Syk) is a critical target protein for treating immunoreceptor signalling-mediated allergies. In this study, a virtual screening of an in-house Chinese medicine database followed by biological assays was carried out to identify novel Syk inhibitors. A molecular docking method was employed to screen for compounds with potential Syk inhibitory activity. Then, an in vitro kinase inhibition assay was performed to verify the Syk inhibitory activity of the virtual screening hits. Subsequently, a ß-hexosaminidase release assay was conducted to evaluate the anti-mast cell degranulation activity of the active compounds. Finally, tanshinone I was confirmed as a Syk inhibitor (IC50 = 1.64 µM) and exhibited anti-mast cell degranulation activity in vitro (IC50 = 2.76 µM). Docking studies showed that Pro455, Gln462, Leu377, and Lys458 were key amino acid residues for Syk inhibitory activity. This study demonstrated that tanshinone I is a Syk inhibitor with mast cell degranulation inhibitory activity. Tanshinone I may be a potential lead compound for developing effective and safe Syk-inhibiting drugs.

Comparison of triple-site ventricular pacing versus conventional cardiac resynchronization therapy in patients with systolic heart failure: A meta-analysis of randomized and observational studies.

BACKGROUND: Conventional cardiac resynchronization therapy (CRT, Bi-V) is associated with no response in about 40% patients due to an insufficient resynchronization. Some studies showed triple-site ventricular (Tri-V) pacing had greater benefits compared with Bi-V pacing, but the results of these studies were conflicting. We hypothesized that Tri-V pacing had greater benefits on long-term outcomes compared with Bi-V pacing in patients with heart failure. METHODS: PubMed, EMBASE, and the Cochrane Library were searched for clinical studies with related outcomes. Weighted mean differences (WMD) and 95% confidence intervals (CIs) were calculated to compare the change in left ventricular ejection fraction (LVEF), left ventricular geometry, functional capacity, and quality of life between Tri-V pacing group and control group. RESULTS: Five trials with 251 patients were included in the analysis. Patients in the Tri-V pacing group had a greater improvement in LVEF (WMD 4.04; 95% CI 2.15-5.92, P < .001) and NYHA classes (WMD -0.27; 95% CI -0.42 to -0.11, P = .001) compared with control group. However, there were no significant differences in left ventricular geometry, six-min walk distance, or Minnesota Living With Heart Failure Questionnaire score between the two groups. The subgroup analyses showed there might be a greater improvement in LVEF in the Tri-V pacing group in patients with QRS duration ≥ 155 ms (WMD 5.60; 95% CI 3.09-8.10, P < .001). CONCLUSIONS: The present analysis suggests that Tri-V pacing has greater benefits in terms of an improvement in LVEF and functional capacity in patients with systolic heart failure, especially in patients with the duration of QRS ≥ 155 ms.

The rational search for PDE10A inhibitors from Sophora flavescens roots using pharmacophore­ and docking­based virtual screening.

Phosphodiesterase 10A (PDE10A) has been confirmed to be an important target for the treatment of central nervous system (CNS) disorders. The purpose of the present study was to identify PDE10A inhibitors from herbs used in traditional Chinese medicine. Pharmacophore and molecular docking techniques were used to virtually screen the chemical molecule database of Sophora flavescens, a well­known Chinese herb that has been used for improving mental health and regulating the CNS. The pharmacophore model generated recognized the common functional groups of known PDE10A inhibitors. In addition, molecular docking was used to calculate the binding affinity of ligand­PDE10A interactions and to investigate the possible binding pattern. Virtual screening based on the pharmacophore model and molecular docking was performed to identify potential PDE10A inhibitors from S. flavescens. The results demonstrated that nine hits from S. flavescens were potential PDE10A inhibitors, and their biological activity was further validated using literature mining. A total of two compounds were reported to inhibit cyclic adenosine monophosphate phosphodiesterase, and one protected against glutamate­induced oxidative stress in the CNS. The remaining six compounds require further bioactivity validation. The results of the present study demonstrated that this method was a time­ and cost­saving strategy for the identification of bioactive compounds from traditional Chinese medicine.

Galectin-3 Predicts Left Ventricular Remodeling of Hypertension.

Previous studies have suggested that galectin-3 is an important mediator of cardiac fibrosis. The aim of this study was to investigate the utility of galectin-3 in identifying early left ventricular remodeling (LVRM) in patients with hypertension. A total of 107 patients with hypertension and 108 controls were enrolled in this study. The levels of galectin-3 were significantly greater in hypertension patients with LVRM compared with those without LVRM. Multivariate regression analysis demonstrated that body mass index and galectin-3 were independent predictors of LVRM in the hypertension group. Only left ventricular mass was independently correlated with serum galectin-3 levels in patients with hypertension. The receiver operating characteristic analysis showed an area under the curve for galectin-3 of 0.698 (P<.001), with an optimal cutoff of 9.43 ng/mL. Therefore, galectin-3 is independently correlated with LVRM and can be regarded as a valuable biomarker of early cardiac remodeling of hypertension.

Hydrophilic gallic acid-imprinted polymers over magnetic mesoporous silica microspheres with excellent molecular recognition ability in aqueous fruit juices.

Hydrophilic molecularly imprinted polymers (MIPs) for gallic acid (GA) were prepared with excellent recognition ability in an aqueous solution. The proposed MIPs were designed by self-polymerization of dopamine (DA) on magnetic mesoporous silica (Fe3O4@SiO2@mSiO2, MMS) using GA as template. Resulting Fe3O4@SiO2@mSiO2@MIPs (MMS-MIPs) were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), vibrating sample magnetometer (VSM), and evaluated by adsorption isotherms/kinetics and competitive adsorption. The adsorption behavior between GA and MMS-MIPs followed Langmuir and Sips adsorption isotherms with a maximum adsorption capacity at 88.7 mg/g and pseudo-second-order reaction kinetics with fast binding (equilibrium time at 100 min). In addition, MMS-MIPs showed rapid magnetic separation (10 s) and stability (retained 95.2% after six cycles). Subsequently, MMS-MIPs were applied for the selective extraction and determination of GA from grape, apple, peach and orange juices (4.02, 3.91, 5.97, and 0.67 µg/g, respectively). Generally, the described method may pave the way towards rationally designing more advanced hydrophilic MIPs.

Novel molecular imprinted polymers over magnetic mesoporous silica microspheres for selective and efficient determination of protocatechuic acid in Syzygium aromaticum.

Improving sites accessibility can increase the binding efficiency of molecular imprinted polymers (MIPs). In this work, we firstly synthesized MIPs over magnetic mesoporous silica microspheres (Fe3O4@mSiO2@MIPs) for the selective recognition of protocatechuic acid (PCA). The resulting Fe3O4@mSiO2@MIPs were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectrometer (FT-IR), thermo-gravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), and vibration sample magnetometer (VSM), and evaluated by adsorption isotherms/kinetics and competitive adsorption. The maximum adsorption capacity of PCA on Fe3O4@mSiO2@MIPs was 17.2mg/g (2.3 times that on Fe3O4@SiO2@MIPs). In addition, Fe3O4@mSiO2@MIPs showed a short equilibrium time (140min), rapid magnetic separation (5s) and high stability (retained 94.4% after six cycles). Subsequently, Fe3O4@mSiO2@MIPs were successfully applied for the selective and efficient determination of PCA (29.3µg/g) from Syzygium aromaticum. Conclusively, we combined three advantages into Fe3O4@mSiO2@MIPs, namely, Fe3O4 core for quick separation, mSiO2 layer for enough accessible sites, and surface imprinting MIPs for fast binding and excellent selectivity, to extract PCA from complex systems.

Efficient determination of protocatechuic acid in fruit juices by selective and rapid magnetic molecular imprinted solid phase extraction coupled with HPLC.

Magnetic molecular imprinted polymers (MMIPs) have been prepared as solid phase material to selectively extract protocatechuic acid (PCA) from fruit juices with high capacity and fast binding kinetics. The resulting MMIPs were characterized by TEM, FT-IR, TGA, and VSM. The adsorption process between PCA and MMIPs followed Langumuir adsorption isotherm with maximum adsorption capacity at 7.5 mg/g and pseudo-second-order reaction kinetics with fast binding kinetics (equilibrium time at 40 min). In addition, the prepared MMIPs showed rapid magnetic separation (10 s) and reusability (retained 94.9% after six cycles). Subsequently, MMIPs were successfully applied for selective enrichment and determination of PCA from fruit juices (0.45 µg/mL in grape juice but not detected in apple juice, pineapple juice, orange juice, and peach juice) with satisfactory recoveries (92-107%). The results indicated that synthesized MMIPs can be used for efficient and selective extraction of PCA from complex matrices.

High-capacity thermo-responsive magnetic molecularly imprinted polymers for selective extraction of curcuminoids.

Thermo-responsive magnetic molecularly imprinted polymers (TMMIPs) for selective recognition of curcuminoids with high capacity and selectivity have firstly been developed. The resulting TMMIPs were characterized by TEM, FT-IR, TGA, VSM and UV, which indicated that TMMIPs showed thermo-responsiveness [lower critical solution temperature (LCST) at 33.71°C] and rapid magnetic separation (5s). The polymerization, adsorption and release conditions were optimized in detail to obtain the highest binding capacity, selectivity and release ratio. We found that the adopted thermo-responsive monomer [N-isopropylacrylamide (NIPAm)] could be considered not only as inert polymer backbone for thermo-responsiveness but also as functional co-monomers combination with basic monomer (4-VP) for more specific binding sites when ethanol was added in binding solution. The maximum adsorption capacity with highest selectivity of curcumin was 440.3µg/g (1.93 times that on MMIPs with no thermosensitivity) at 45°C (above LCST) in 20% (v/v) ethanol solution on shrunk TMMIPs, and the maximum release proportion was about 98% at 20°C (below LCST) in methanol-acetic acid (9/1, v/v) solution on swelled TMMIPs. The adsorption process between curcumin and TMMIPs followed Langumuir adsorption isotherm and pseudo-first-order reaction kinetics. The prepared TMMIPs also showed high reproducibility (RSD<6% for batch-to-batch evaluation) and stability (only 7% decrease after five cycles). Subsequently, the TMMIPs were successfully applied for selective extraction of curcuminoids from complex natural product, Curcuma longa.

Preparation of magnetic dummy molecularly imprinted polymers for selective extraction and analysis of salicylic acid in Actinidia chinensis.

Compounds with strong intramolecular hydrogen bonds (e.g., salicylic acid) have weak intermolecular hydrogen bonding interactions between them and functional monomers in the imprinting process. Consequently, the corresponding molecularly imprinted polymers (MIPs) have no specific adsorption ability. Here, the first magnetic dummy MIPs (MDMIPs) based on benzonic acid as dummy template are successfully developed and evaluated with respect to the applications in selective enrichment and analysis of salicylic acid from complex mixtures. Various parameters affecting absorption/desorption were evaluated for achieving optimal recovery and reducing nonspecific interactions. The prepared MDMIPs showed high adsorption capacity, good selectivity, rapid kinetic binding (40 min) and magnetic separation (5 s), high reproducibility (RSD< 4 % for batch-to-batch evaluation), and stability (only 4 % decrease after 6 cycles). Owing to the efficacy in specific binding and removal of interference, trace level salicylic acid was quantified (0.2 µg/g of fresh mass) in Actinidia chinensis by high-performance liquid chromatography.

Integration of magnetic solid phase fishing and off-line two-dimensional high-performance liquid chromatography-diode array detector-mass spectrometry for screening and identification of human serum albumin binders from Radix Astragali.

Radix Astragali is one of the most popular traditional medicinal herb and healthy dietary supplement. Isoflavonoids and astragalosides are the main bioactive ingredients. However, the systematic bioactive component analysis is inadequate so far. Then a facile method based on Fe3O4@SiO2-human serum albumin (Fe3O4@SiO2-HSA) magnetic solid phase fishing integrated with two-dimensional high-performance liquid chromatography-diode array detector-mass spectrometry (2D HPLC-DAD-MS(n)) was developed to fish out and identify HSA binders from Radix Astragali. The immobilized HSA displayed a high stability with 96.2% retained after ten consecutive cycles. 2D HPLC system (size exclusion chromatography×reversed phase chromatography, SEC×RP) were developed and optimised. Forty-seven bioactive compounds including thirty-four isoflavonoids and thirteen astragalosides were screened and identified or tentatively deduced based on their retention time, ultraviolet (UV), accurate molecular weight and diagnostic fragment ions. The results indicated that the integrated method could be widely applied for systematical fishing and identification of bioactive compounds, especially for low-abundance and overlapped compounds, from complex mixtures.