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Gao Q.,Wuhan University | Luo D.,Wuhan University | Luo D.,COE Limited | Bai M.,Wuhan University | And 2 more authors.
Journal of Agricultural and Food Chemistry | Year: 2011

In this study, a nanocomposite of polypyrrole-coated magnetite nanoparticles (denoted as MNPs/PPy) was prepared and employed as magnetic solid-phase extraction (MSPE) sorbent for extraction of estrogens from milk samples. Because the polypyrrole coating possessed a highly π-conjugated structure and hydrophobicity, MNPs/PPy showed excellent performance for the estrogen extraction. Estrogens could be captured directly by MNPs/PPy from milk samples without protein precipitation. Moreover, the extraction could be carried out within 3 min. Thus, a rapid, simple, and effective method for the analysis of estrogens in milk samples was established by coupling MNPs/PPy-based MSPE with liquid chromatography-tandem mass spectrometry (LC-MS/MS). The limits of detections for estrogens investigated were in the range of 5.1-66.7 ng/L. The recoveries of estrogens (concentration range of 0.5-20 ng/mL) from milk samples were in the range of 83.4-108.5%, with relative standard deviations ranging between 4.2 and 15.4%. © 2011 American Chemical Society.


Xiang Q.,Wuhan University | Hashi Y.,COE Limited | Chen Z.,Wuhan University
Journal of Separation Science | Year: 2016

A rapid and sensitive ultra high performance liquid chromatography with electrospray ionization tandem mass spectrometry method was developed and validated for the simultaneous determination of eight major active components (magnoflorine, menisperine, 20-hydroxyecdysone, cepharanthine, columbamine, jatrorrhizine, columbin, and palmatine) in Radix Tinosporae. The separation was performed on an InterSustainSwift C18 column (1.9 μm, 2.1 id × 100 mm) at 40 °C with a gradient elution. A mixture of acetonitrile and methanol (v/v = 1:1) and ammonium acetate buffer (25 mmol/L ammonium acetate with 0.2% formic acid) were used as mobile phases, and the flow rate was set at 0.4 mL/min. The recovery was tested in real samples and calculated to be 86.97-111.28%, and all the compounds showed good linearity (r > 0.998) in relatively wide concentration ranges. The developed method was applied to the determination of eight active compounds in real herb samples, which were collected from four different places. It has been demonstrated that the proposed method has great potential for the quality control of the traditional Chinese medicine Radix Tinosporae. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Cai B.-D.,Wuhan University | Zhu J.-X.,Wuhan University | Gao Q.,Wuhan University | Luo D.,COE Limited | And 2 more authors.
Journal of Chromatography A | Year: 2014

A rapid method was developed for determination of endogenous cytokinins (CKs) based on magnetic solid-phase extraction (MSPE) followed by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). We illustrated the hydrophilic character of bare Fe3O4 nanoparticles that were directly used as a MSPE sorbent for rapid enrichment of endogenous CKs from complex plant extract. To the best of our knowledge, this is the first report of bare Fe3O4 directly used as efficient extraction sorbent to enrich target CKs based on hydrophilic interaction. Under the optimized conditions, a rapid, sensitive and high-throughput method for the determination of 16 CKs was established by combination of MSPE with UPLC-MS/MS. Good linearity was obtained with correlation coefficients (r) from 0.9902 to 0.9998. The limits of detection (LODs) and quantification (LOQs) ranged from 1.2pgmL-1 to 391.3pgmL-1 and 4.1pgmL-1 to 1304.3pgmL-1, respectively. 16 CKs could be successfully determined in spiked sample with 80.6-117.3% recoveries and the relative standard deviations (RSDs) were less than 16.6%. Finally, 10 endogenous CKs were successfully quantified in 50mg Oryza sativa sample using the developed MSPE-UPLC-MS/MS method. © 2014 Elsevier B.V.


Ma W.,Wuhan University | Fu S.,Wuhan University | Hashi Y.,COE Limited | Chen Z.,Wuhan University
Journal of Agricultural and Food Chemistry | Year: 2013

A GC/MS method with monolithic material sorptive extraction (MMSE) pretreatment was developed to determine contents of the enantiomers of jasmonic acid and methyl jasmonate in flowers. To optimize MMSE extraction, several MMSE parameters were investigated, including extraction temperature, extraction time, and extraction solvent. Under the optimal conditions, extraction efficiency was good. Using the selected-ion monitoring mode, the limit of detection (LOD, S/N = 3) for methyl jasmonates was 0.257 ng/mL. The limit of quantitation (LOQ, S/N = 10) was 0.856 ng/mL. The linearity range was 1-100 ng/mL. The average recovery of methyl jasmonate at lower concentration was 116.8% (2 ng/mL). The relative standard deviation of methyl jasmonate contents determined within the linear range of detection was less than or equal to 15% of the mean determined level. The proposed method is rapid, sensitive, and competently applied to the determination of jasmonic acid and methyl jasmonate enantiomers in flowers. © 2013 American Chemical Society.


Gao Q.,Wuhan University | Lin C.-Y.,Wuhan University | Luo D.,COE Limited | Suo L.-L.,Wuhan University | And 2 more authors.
Journal of Separation Science | Year: 2011

A novel magnetic material Fe3O4/SiO 2/P(MAA-co-VBC-co-DVB) was prepared via the hypercrosslinking of its precursor which was produced via precipitation polymerization of methacrylic acid (MAA), vinylbenzyl chloride (VBC), and divinylbenzene (DVB) in the presence of Fe3O4/SiO2 submicrospheres with the surface containing abundant reactive double bonds. The resultant sorbent was characterized by scan electron microscopy, N2 adsorption, and Fourier transform infrared spectroscopy. It was found that this material had remarkable features such as large surface area (500m2/g) and pore volume (0.32 cm3/g), as well as desirable chemical composition (including hydrophobic and ion-exchange moieties). Taking advantages of the Fe 3O4/SiO2/P(MAA-co-VBC-co-DVB), a magnetic SPE (MSPE) coupled with capillary electrophoresis (CE) method was developed for the determination of illegal drugs in urine samples. The extraction time could be clearly shortened up to 3 min. The recoveries of these drug compounds were in the range of 84.0-123% with relative standard deviations ranging between 1.7 and 10.5%; the limit of detection was in the range of 4.0-6.0 mg/L. The proposed method is simple, effective, and low-cost, and provides an accurate and sensitive detection platform for abused drug analysis. © 2011 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim.


Gao Q.,Wuhan University | Zheng H.-B.,COE Limited | Luo D.,Wuhan University | Ding J.,Wuhan University | Feng Y.-Q.,Wuhan University
Analytica Chimica Acta | Year: 2012

In this work, we proposed a simple co-mixing method to fabricate magnetic one-dimensional polyaniline (denoted as 1D-PANIs/MNPs). One-dimensional polyanilines (1D-PANIs) and magnetic nanoparticles (MNPs) were prepared by chemical oxidation and solvothermal methods, respectively. When MNPs and 1D-PANIs (with mass ratio 4:1) were co-mixed and vortexed evenly in a solvent (e.g., ethanol, water, acetonitrile), they could assemble into 1D-PANIs/MNPs spontaneously and thus be magnetically separable. To testify the feasibility of 1D-PANIs/MNPs in sample preparation, it was applied as the sorbent for magnetic solid phase extraction (MSPE) of fluoroquinolones (FQs) in honey samples. Under optimized conditions, a rapid, convenient, and efficient method for the determination of four FQs in honey samples by 1D-PANIs/MNPs-based MSPE coupling with high performance liquid chromatography with fluorescence detection (HPLC-FLD) was established. The limits of detection (LODs) for four FQs ranged from 0.4 to 1.4ngg -1. The intra- and interday relative standard deviations (RSDs) were less than 17.6%. The recoveries of FQs for three spiked honey samples ranged from 86.3 to 121.3%, with RSDs of less than 16.3%. © 2012 Elsevier B.V.


Ding J.,Wuhan University | Gao Q.,Wuhan University | Luo D.,Wuhan University | Luo D.,COE Limited | And 2 more authors.
Journal of Chromatography A | Year: 2010

A new sorbent for magnetic solid-phase extraction, n-octadecylphosphonic acid modified mesoporous magnetic nano particles (OPA/MMNPs), was easily prepared via a two-step strategy. MMNPs were synthesized by a solvent-thermal process, and then OPA was grafted onto the surface of MMNPs via the strong Lewis acid/base interaction. The resultant material was characterized by transmission electron microscopy, tensionmeter, Fourier-transform infrared spectroscopy, vibrating sample magnetometry, elemental analysis, and nitrogen adsorption analysis. The results demonstrated that the particles exhibited mesoporous structure, superparamagnetic (57emu/g) and extremely hydrophobic (water contact angle of 136°) properties. To evaluate the extraction performance of the resultant sorbent, polycyclic aromatic hydrocarbons (PAHs) were chosen as model analytes. The extraction conditions were optimized. Based on these, a rapid, convenient and efficient method for the determination of PAHs in water samples was established by combination of magnetic solid-phase extraction and gas chromatography-mass spectroscopy. The linearity range of proposed method was 0.2-100μg/L with correlation coefficients (R2) of 0.9726-0.9970. The intra- and inter-day relative standard deviations (RSDs) were less than 17.6%. Batch-to-batch reproducibility was acceptable with RSD values less than 12.1%. © 2010 Elsevier B.V.


Gao Q.,Wuhan University | Luo D.,Wuhan University | Luo D.,COE Limited | Ding J.,Wuhan University | Feng Y.-Q.,Wuhan University
Journal of Chromatography A | Year: 2010

A novel magnetic solid-phase extraction (MSPE) sorbent, magnetite/silica/poly (methacrylic acid-co-ethylene glycol dimethacrylate) (Fe3O4/SiO2/P(MAA-co-EGDMA)), was developed. This MSPE material was prepared by distillation-precipitation polymerization of MAA and EGDMA in the presence of Fe3O4/SiO2 microspheres with the surface containing abundant reactive double bonds. The resultant sorbent material was characterized by elemental analysis, electron microscopy, X-ray diffraction and Fourier-transformed infrared spectroscopy. In this work, eleven sulfonamides (SAs) were selected as model analytes to validate the extraction performance of this new MSPE sorbent. Noticeably, the extraction can be carried out quickly, the extraction time for the SAs onto Fe3O4/SiO2/P(MAA-co-EGDMA) sorbent can be clearly shortened to 0.5min. The desorption solution of SAs was analyzed by LC-MS/MS, and the results showed that the recoveries of these compounds were in the range of 87.6-115.6%, with relative standard deviations ranging between 0.9% and 10.8%; the limit of detection were in the range of 0.5-49.5ng/L. © 2010 Elsevier B.V.


Vadiraj A.,COE Limited
SAE Technical Papers | Year: 2016

This article delineates the importance of infrastructure and its related aspects on sustainability of transportation on global and local context. Almost 7% of the GDP in India is spent on transportation and 6% of the CO2 emissions in the world is due to transportation. In countries like India, the road transport has significantly grown over other forms of mobility. This articles introduces different forms of transportations that exists today and the importance of sustainability in transportation sector. Sustainable transportation depends on development of infrastructure to enable smart transport solutions involving intelligent transport system, electric mobility, information management, vehicle health monitoring, advanced traffic management system and driver assistance system in a vehicle. The challenges includes existing transport operations, environmental impact and complexity of existing transport network. Future sustained mobility should gradually move towards alternate energy source preferably hydrogen and fuel cell based systems. Several demonstrations has been observed around the world in transport sector with non-carbon based energy source for mass mobility. This articles gives several such interesting examples. Future recommendations in this article promotes powered bicycles, cable cars and dual mode vehicles as a means of sustained mobility. Other recommendations includes economy mode in vehicles to save fuel, double decker coaches for suburban railways to reduce road commuters, work clusters for service sectors as an alternate means for reducing road traffic and pollution. Copyright © 2016 SAE International.


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