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Zhu B.,Zhejiang Institute for Food and Drug Control | Ryan D.K.,University of Massachusetts Lowell
Journal of Environmental Radioactivity | Year: 2016

The development of chemometric methods has substantially improved the quantitative usefulness of the fluorescence excitation-emission matrix (EEM) in the analysis of dissolved organic matter (DOM). In this study, Regional Integration Analysis (RIA) was used to quantitatively interpret EEMs and assess fluorescence quenching behavior in order to study the binding between uranyl ion and fulvic acid. Three fulvic acids including soil fulvic acid (SFA), Oyster River fulvic acid (ORFA) and Suwannee River fulvic acid (SRFA) were used and investigated by the spectroscopic techniques. The EEM spectra obtained were divided into five regions according to fluorescence structural features and two distinct peaks were observed in region III and region V. Fluorescence quenching analysis was conducted for these two regions with the stability constants, ligand concentrations and residual fluorescence values calculated using the Ryan-Weber model. Results indicated a relatively strong binding ability between uranyl ion and fulvic acid samples at low pH (log K value varies from 4.11 to 4.67 at pH 3.50). Fluorophores in region III showed a higher binding ability with fewer binding sites than in region V. Stability constants followed the order, SFA > ORFA > SRFA, while ligand concentrations followed the reverse order, SRFA > ORFA > SFA. A comparison between RIA and Parallel Factor Analysis (PARAFAC) data treatment methods was also performed and good agreement between these two methods (less than 4% difference in log K values) demonstrates the reliability of the RIA method in this study. © 2015 Elsevier Ltd.

Xi L.,Zhejiang University | Ren D.,Zhejiang University | Luo J.,Zhejiang Institute for Food and Drug Control | Zhu Y.,Zhejiang University
Journal of Electroanalytical Chemistry | Year: 2010

The electrosynthesis of polyaniline (PANI) film has been achieved on glassy carbon electrode (GCE) in a novel ionic liquid medium by means of cyclic voltammetry (CV). Then a copper nanoparticles (Cu-NPs) film was in situ electrochemically deposited on the surface of PANI/GCE. Electrochemical behavior and surface characteristics of the Cu-NPs/PANI/GCE were studied using cyclic voltammetry, scanning electron microscopy (SEM) and the results confirmed the presence of PANI and Cu-NPs on the electrode surface. Cu-NPs were highly dispersed and firmly stabilized by surface attachment of the PANI, which was prepared in ionic liquid and strongly attached to the electrode surface. The Cu-NPs/PANI/GCE showed excellent electrocatalytic activity toward the oxidation of ascorbic acid (AA) under weakly basic conditions. Amperometry was carried out to determine the concentration of AA at 0.2 V, and a good linear concentration range from 0.005 to 3.5 mM was found. The Cu-NPs/PANI composite film on GCE surface showed good reproducibility and stability. © 2010 Published by Elsevier B.V.

Deng Z.Y.,Zhejiang University of Technology | Deng Z.Y.,Zhejiang Institute for Food and Drug Control | Hu M.M.,Zhejiang University of Technology | Hu M.M.,Zhejiang Institute for Food and Drug Control | And 2 more authors.
Inflammation Research | Year: 2015

Objective: Atherosclerosis (AS) is an inflammatory disease involved in vascular inflammatory injury. The inflammasome is an important part of inflammatory diseases and participates in the vascular inflammatory injury. Resveratrol (RSV) possesses anti-inflammatory activities, but its effects on inflammasomes during vascular injury remain unclear. This study focused on the effects and mechanisms of RSV on inflammasomes during vascular injury. Methods: Male Sprague–Dawley rats were treated with a purified diet or cholesterol-enriched diet combined with vitamin D2 (VD; 1.8 million units/kg/days, Po) and saline or RSV (50 mg/kg/days, Po) daily for 5 weeks. The concentrations and enzyme activities of related indicators were measured by a spectrophotometer or ELISA kit. Their gene and protein expression levels were analyzed by reverse transcription–polymerase chain reaction and Western blot, respectively. Results: Upon administration with RSV, rats with combined hyper cholesterol and VD demonstrated the following changes: the vascular histopathological changes were relieved, and the level of the von Willebrand factor decreased. The level of serum IL-1β, a marker of inflammasome activation, significantly decreased. The mRNA and protein expression levels of the three components of inflammasomes, namely, NOD-like receptor pyrin domain containing 3, apoptosis-associated speck-like protein containing a caspase-recruitment domain, and caspase-1, were downregulated. The effects of RSV were closely related to hypolipidemia (decrease in the levels of total cholesterol, triglycerides, and low-density lipoprotein cholesterol combined with the expression of the lectin-like ox-LDL receptor and increase in high-density lipoprotein cholesterol), antioxidation (decrease in MDA levels and increase in SOD and GPx activities), and anti-inflammation (downregulation of the expression of IL-1β, intracellular adhesion molecule-1, and monocyte chemotactic protein-1). The mechanisms for the downregulation of NF-κB p65 and p38 MAPK expression, as well as the upregulation of SIRT1 expression, were analyzed. Conclusion: This study proved that RSV inhibited inflammasome activation to protect vascular injury in vivo. RSV exhibited therapeutic potential in the treatment of vascular injury. © 2015, Springer Basel.

Zhu P.-X.,Zhejiang Institute for Food and Drug Control | Jiang K.-Z.,Hangzhou Normal University | Zheng J.-Q.,Zhejiang Institute for Food and Drug Control | Wang F.,Zhejiang Institute for Food and Drug Control | And 3 more authors.
Journal of Chinese Mass Spectrometry Society | Year: 2014

A method of liquid chromatography-mass spectrometry was developed for separation and differentiation of the Z/E isomers of bulk cefprozil and its intermediate substance (6R, 7R)-7-amino-8-oxo-3-(1-propenyl) -5-thia-1-azabicyclo [4.2.0] oct-2-ene-2-carboxylic acid (7-APRA). For the 7-APRA isomers, both of the deprotonated molecules are favorable to undergo fragmentation via losing H2S and OCNH, and give the product ions at the m/z 161and m/z 152, respectively. Different to the E isomer, the Z isomer of 7-APRA is facile to undergo γ-H migration, which promotes the H2S elimination. As a result, Z-7-APRA has the significantly higher abundance ratio of [I161/I152] than the E isomer, which can be used for isomer differentiation. Analogously, the deprotonated cefprozil Z isomer is also more favorable to undergo dissociation to form the ion of m/z 205, due to the phenol function group in the structure. Furthermore, their fragmentation mechanisms were proposed, and the density functional theory (DFT) calculations were employed to consist with the experimental results.

Ma L.-K.,Zhejiang Institute for Food and Drug Control | Li W.-T.,Zhejiang Institute for Food and Drug Control | Zhao W.-L.,Zhejiang Institute for Food and Drug Control
Chinese Traditional and Herbal Drugs | Year: 2014

Objective: To develop an analysis method based on N-propylethylenediamine (PSA)-HPLC-QQQ-MS/MS for the determination of 12 kinds pesticide residues in Fritiliariae Thunbergii Bulbus and to quantify them in 20 batches of Fritiliariae Thunbergii Bulbus produced in various places in Zhejiang province. Methods: Fritiliariae Thunbergii Bulbus samples were extracted with acetonitrile and purified by the small column of PSA. The prepared samples were analyzed by HPLC-QQQ-MS/MS in multiple reaction monitoring (MRM) mode, and the pesticides were qualitified by the internal standard method. Results: All the 12 pesticides showed good linearities in their reasonable range (r = 0.9986-0.9998), and the average recoveries of all the pesticides were in the range of 68.1%-108.0% at three spiked levels of 90, 300, and 900 ng/mL. The RSD values were in the range of 1.1%-6.1%, and the LODs of each pesticide were all in the range of 0.08-1.0 μg/kg. Conclusion: The method is suitable for the multiresidues analysis of pesticides in Fritiliariae Thunbergii Bulbus simultaneously and the quality of Fritiliariae Thunbergii Bulbus is basically good for the safty although it contains a trace of several pesticide residues.

Deng M.,Zhejiang Medical College | Cheng W.,Zhejiang Institute for Food and Drug Control
Asian Journal of Chemistry | Year: 2015

Bioactivity-guided isolation and purification of EtOAc layer of Chrysanthemum maximum resulted in six components, among which four were flavonoids and two were phenolic acids. These components were identified to be isoquercitrin (1), hyperin (2), chlorogenic acid (3), caffeic acid (4), quercetin (5) and isorhamnetin (6) through physicochemical properties. The compounds 1-3 and 5 were all isolated from the plant for the first time and tested for their relative bioactivities. © 2015, Chemical Publishing Co. All rights reserved.

Chen X.,Zhejiang University | Han C.,Hangzhou Normal University | Cheng H.,Hangzhou Normal University | Wang Y.,Hangzhou Normal University | And 3 more authors.
Journal of Chromatography A | Year: 2013

In this work, a hybrid method for the rapid speciation of mercury compounds by cation exchange chromatographic separation and inductively coupled plasma mass spectrometry (ICP-MS) detection is reported. Effective separation of inorganic mercury (Hg2+), methylmercury (MeHg), ethylmercury (EtHg) and phenylmercury (PhHg) within 2-2.5min was achieved on two consecutive 12.5-mm strong cation exchange guard columns with 2.0mM l-cysteine or thiourea (pH 2.0) as the mobile phase. This separation met the requirements of green analytical chemistry such as the prevention of toxic waste, safer HPLC mobile phases, and short separation times to reduce operating costs. The detection limits for Hg2+, MeHg, EtHg and PhHg were 0.019, 0.027, 0.031 and 0.022μgL-1, each, and the repeatabilities of peak height and peak area (5.0μgL-1 for each Hg species) were all lower than 3%. Contents of Hg species and total mercury in certified reference materials of seawater (GBW(E) 080042) and fish tissue (GBW 10029) were in good accordance with the certified values, and satisfactory recoveries (96-102% for GBW(E) 080042 and 94-101% for GBW 10029) validated the developed method. The developed method was applied for the speciation of mercury in five seawater sample and five marine fish samples. The concentrations of mercury species in all analyzed fish samples did not exceed the permissible levels of the National Standard of China. © 2013 Elsevier B.V.

Zhang D.,Zhejiang University | Lu Y.,Zhejiang University | Jiang J.,Urbana University | Zhang Q.,Zhejiang University | And 6 more authors.
Biosensors and Bioelectronics | Year: 2015

The nanoscale Lycurgus cup arrays were hybrid structures of nanocups and nanoparticles with ultrasensitivity to refractive index change. In this study, an electrochemical localized surface plasmon resonance (LSPR) sensor was developed by coupling electrochemistry to LSPR spectroscopy measurement on the nanoscale cup arrays (nanoCA). Based on the combination of electrochemistry and LSPR measurement, the electrochemical LSPR on nanoCA was observed with significant resonance wavelength shifts in electrochemical modulation. The synchronous implementation of cyclic voltammetry and optical transmission spectrum can be used to obtain multiply sensing information and investigate the enhancement for LSPR from electrochemical scanning. The electrochemical enhanced LSPR was utilized as biosensor to detect biomolecules. The electrochemical LSPR biosensor with synchronous electrochemical and optical implement showed higher sensitivity than that of conventional optical LSPR measurement. Detecting with multi-transducer parameters and high sensitivity, the electrochemical LSPR provided a promising approach for chemical and biological detection. © 2014 Elsevier B.V.

Wang J.,Zhejiang Institute for Food and Drug Control | Ruan D.,Zhejiang University of Technology | Shan W.,Zhejiang University of Technology
Journal of Liquid Chromatography and Related Technologies | Year: 2013

The twelve impurities and isomers in cefmenoxime hydrochloride were separated and identified by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MSn). A discipline of mass fragmentation pattern and structure for the E-isomer and Δ3-isomer of oxime cephalosporin antibiotics was presented to distinguish their structures. The column was Alltima C18(250 × 4.6 mm, 5m). The mobile phase was water-acetic acid-acetonitrile (85:1:15). In positive mode, full scan LC-MS was first performed in order to obtain the m/z value of the protonated molecules of all detected peaks. LC-MS-MS and LC-MS-MS-MS were then carried out on the compounds of interest. The complete fragmentation patterns of twelve impurities were studied and used to obtain information about the structure of these impurities. The relationship of mass fragmentation pattern and structure for cefmenoxime, E-isomer of cefmenoxime and Δ3-isomer of cefmenoxime was studied. The structures of the twelve impurities and isomers in cefmenoxime hydrochloride were deduced based on the HPLC-MSn data, assisted by the UV spectra and stress testing. © 2013 Copyright Taylor and Francis Group, LLC.

Sun J.,Zhejiang University of Technology | Wang Q.,Zhejiang Institute for Food and Drug Control | Zhuang S.,Zhejiang University | Zhang A.,Zhejiang University of Technology
Environmental Pollution | Year: 2016

This study investigated the occurrence of 8 polybrominated diphenyl ether (PBDE) congeners from homes (n = 20), offices (n = 20), air conditioners (n = 6), and computers (n = 6). High detection frequencies for most of the congeners were observed, indicating continued widespread use of Penta-, Octa- and Deca-BDE mixtures. The median concentrations of ∑PBDEs were 119 and 194 pg m−3 for home air and office air, respectively. Regarding dust, the median concentrations of ∑PBDEs were 239 and 437 ng g−1 for home and office dust, respectively. The ratios of the median concentrations of BDE-209 to ∑PBDEs were approximately 0.95 and 0.87 for home dust and office dust, respectively. The median concentrations of ∑PBDEs were 359 ng g−1 and 350 ng g−1 for dust on air conditioner filters and the back cabinet of the computer, respectively. The ratios of the median concentrations of BDE-209 to ∑PBDEs were approximately 0.58 and 0.46 for air conditioner and computer samples. Running air conditioners contributed to ΣPBDEs in office air through direct and indirect pathways. The daily intake of PBDEs was estimated to be 2630 pg (kg bw)−1 day−1 for toddlers in homes and 319 pg (kg bw)−1 day−1 for adults in homes and offices. © 2016 Elsevier Ltd

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