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Li H.,Yancheng Institute of Technology | Zhang X.,Yancheng Institute of Technology | Zhang L.,Yancheng Entry Exit Inspection and Quarantine Bureau | Wang X.,Huaian Entry Exit Inspection and Quarantine Bureau | And 4 more authors.
Analytica Chimica Acta | Year: 2017

A silica stationary phase was designed and synthesized through the co-functionalization of silica with Wulff-type phenylboronate and C12 for mixed-mode liquid chromatography applications. The as-synthesized stationary phase was characterized by elemental analysis and Fourier Transform-InfraRed Spectroscopy (FT-IR). Retention mechanisms, including boronate affinity (BA), reversed-phase (RP) and anion-exchange (AE), were involved. Retention mechanism switching was easily realized by adjustment of the mobile phase constitution. Cis-diol compounds could be selectively captured under neutral conditions in BA mode and off-line separated in RP mode. Neutral, basic, acidic and amphiprotic compounds were chromatographed on the column in RP chromatography, while inorganic anions were chromatographed in AE chromatography to characterize the mixed-mode nature of the prepared stationary phase. In addition, the RP performance was compared with an octadecyl silica column in terms of column efficiency (N/m), asymmetry factor (Af), retention factor (k) and resolution (Rs). The prepared stationary phase offered multiple interactions with analytes in addition to hydrophobic interactions under RP elution conditions. Based on the mixed-mode properties, off-line 2D-LC, for selective capture and separation of urinary nucleosides, was successfully realized on a single column, demonstrating its powerful application potential for complex samples. © 2017 Elsevier B.V.

Ding J.,Changzhou University | Yuan L.,Jiangsu University | Gao L.,Yancheng Entry exit Inspection and Quarantine Bureau | Chen J.,Yancheng Institute of Technology
Journal of Luminescence | Year: 2012

A new rhodamine derivative (RhB-Im) was synthesized as an on-off chemosensor for Cu 2+ in an acidic aqueous solution. RhB-Im exhibited chemically reversible and highly selective and sensitive fluorescence response toward Cu 2+ in aqueous acetate-buffer/DMF solution (pH 3.6) over other competitive metal ions. Upon addition of Cu 2+, RhB-Im displayed remarkable fluorescence quenching accompanied by a clear color change from pink to red. Based on the analysis of Stern-Volmer plots, a static quenching mode was proposed to be primarily responsible for the fluorescence quenching event when the concentration of Cu 2+ was low, but, the energy- and electron-transfer processes cannot be ruled out. © 2012 Elsevier B.V. All rights reserved.

PubMed | Yancheng Entry Exit Inspection and Quarantine Bureau, Yancheng Institute of Technology and Huaian Entry Exit Inspection and Quarantine Bureau
Type: | Journal: Journal of chromatography. A | Year: 2016

In this study, a boronate affinity silica stationary phase with enhanced binding properties towards cis-diol compounds was prepared through the combination of surface-initiated atom transfer radical polymerization (SI-ATRP) with a Wulff-type boronate as affinity ligand. The stationary phase showed good hydrophilicity and improved binding strength toward adenosine, with binding constant to be as low as 2.3810

Xu S.,Nanjing University of Science and Technology | Liu D.-B.,Nanjing University of Science and Technology | Wang X.-F.,Xi'an Modern Chemistry Research Institute | Wang J.-L.,Xi'an Modern Chemistry Research Institute | And 2 more authors.
Tuijin Jishu/Journal of Propulsion Technology | Year: 2011

External fire tests were performed to determine the applicability of heat flux estimation method to propellants. The heat fluxes of three propellants were measured by a radiometer and calculated through the estimation method respectively. The average values of measured heat fluxes were 2.87kW/m2, 2.65kW/m2 and 3.44kW/m2, while the corresponding calculated values were 4.06kW/m2, 7.62kW/m2 and 3.67kW/m2. The results show that, as the burning time is greater than 5s, the calculated heat flux is in accordance with the measured value; and as the burning time is less than or equal to 5s, measuring the heat flux by radiometer is proposed, because the ratio of radiant heat to combustion heat used in estimation method (0.33) is greater than the actual ratio, and it will lead an abnormal calculated value.

Pan J.,Jiangsu University | Luo J.,Jiangsu University | Cao J.,Yancheng Entry Exit Inspection and Quarantine Bureau | Liu J.,Jiangsu University | And 3 more authors.
RSC Advances | Year: 2016

Hydrophilic urea-formaldehyde macroporous foams (UFMF) were simply synthesized by templating oil-in-water Pickering high internal phase emulsions (HIPEs) solely stabilized by lignin particles. Morphology and structure of the UFMF can be easily tailored by varying the experimental compositions of Pickering HIPEs and polymerization time. Due to their porous matrix, hydrophilic surface, and high content of binding groups (such as hydroxyl groups and carbonyl groups), as-prepared UFMF was adopted for the removal of three phenolic compounds (PCs) from aqueous solution. The influences of pH, solution temperature, contact time, and initial concentration of 2,4,5-trichlorophenol (2,4,5-TCP), 2,4,6-trichlorophenol (2,4,6-TCP) and 4-nitrophenol (4-NP) on adsorption capacity and competitive adsorption of multi PCs were investigated via the batch mode experiments. The adsorption kinetics and adsorption isotherms fit well by a pseudo-second-order model and Langmuir model, respectively. The max adsorption capacity of 2,4,5-TCP, 2,4,6-TCP and 4-NP at 25 °C are 116.3 mg g-1, 78.74 mg g-1, 29.41 mg g-1, respectively, and their adsorption rate follows the order 2,4,5-TCP > 2,4,6-TCP > 4-NP. Moreover, the group type and position effects both influence the adsorption, and follow the order: 2,4,5-position substitution of chloride > 2,4,6-position substitution of chloride > 4-position substitution of nitro-group, showing that the substitution with the more groups has the higher adsorption affinity. © 2016 The Royal Society of Chemistry.

Pan J.,Jiangsu University | Qu Q.,Jiangsu University | Cao J.,Yancheng Entry Exit Inspection and Quarantine Bureau | Yan D.,Jiangsu University | And 3 more authors.
Chemical Engineering Journal | Year: 2014

The water-in-oil Pickering high internal phase emulsions (HIPEs) were firstly stabilized by hydrophobic silica particles with adding small amounts of nonionic surfactant Hypermer 2296. Then molecularly imprinted polymer foams (MIPFs) derived from Pickering HIPEs were evaluated as adsorbents for the selective adsorption of λ-cyhalothrin. The results of characterization indicated that MIPFs possessed open-cell structure, interconnecting pores, thermal stability, moderate hydrophobicity and mechanical robust. The adsorption capacity for λ-cyhalothrin were closely related with the morphologies of the MIPFs, such as void diameter and interconnectivity, which could be easily tailored by varying the parameters of Pickering HIPEs. The batch mode experiments proved that as-prepared MIPFs exhibited the excellent adsorption capacity for λ-cyhalothrin (46.10μmolg-1 at 25°C) and enhanced recognition towards λ-cyhalothrin over fenvalerate and diethyl phthalate. © 2014 Elsevier B.V.

Wang T.,Jiangsu University | Zhang D.,Yancheng Entry Exit Inspection and Quarantine Bureau | Zhang Z.,Jiangsu University | Han J.,Jiangsu University | And 2 more authors.
Journal of the Iranian Chemical Society | Year: 2016

As a novel and green pretreatment technique to trace samples, polyoxyethylene cetyl ether (POELE20)–(NH4)2SO4 aqueous two-phase extraction system was coupled with high-performance liquid chromatography to analyse synchronously chloramphenicol (CAP), thiamphenicol (TAP) and florfenicol (FF) in chicken and pork samples. It was found that the extraction efficiency (E%) and enrichment factor (F) of the three antibiotics were influenced by the types of salts, the concentration of salt, the concentration of POELE20, system temperature and pH. The final optimal condition was as following: the phase-forming salt is (NH4)2SO4, the concentration of (NH4)2SO4 is 0.141 g mL−1, the concentration of POELE20 is 0.03 g mL−1, the temperature is 298.15 K, and the system pH is 4.5. This POELE20–(NH4)2SO4 ATPS was applied to separate and enrich three antibiotics in real sample under the optimal conditions, and it was found that the recovery was 97.20–102.00 % with a RSD of 0.61–4.85 %. The limit of detection for CAP, TAP and FF were 0.10, 0.50 and 0.50 μg kg−1, and the limit of quantitation for CAP, TAP and FF was 0.15, 1.50 and 1.50 μg kg−1. Seven times the experiments were used to verify the repeatability and veracity of this method, and the RSD for the intra-day and inter-day were 1.13–3.22 and 1.74–4.72 %. © 2016, Iranian Chemical Society.

Wang T.,Jiangsu University | Han J.,Jiangsu University | Tian Y.,Jiangsu University | Zhang D.,Yancheng Entry Exit Inspection and Quarantine Bureau | And 3 more authors.
Separation Science and Technology (Philadelphia) | Year: 2016

This paper established a viable process for the simultaneous reaction, extraction, and primary purification of lutein in marigold flower by the isopropanol–KOH aqueous two-phase system (ATPS). In this process, the liposoluble lutein esters were translated into water-soluble lutein by saponification reaction in ATPS and distributed to the top phase. Meanwhile, the water-soluble flavonoids in marigold were also extracted and distributed to the bottom phase. The concentrations of phase-forming isopropanol and KOH, the added mass of marigold flower powder, temperature, and time were investigated to evaluate their effects on the extraction and partition behaviour of lutein and flavoniods in ATPS. Under the optimal conditions (38% isopropanol, 18% KOH, 0.05 g of marigold flower powder, 500°C and 1.5 h extraction time), the leaching efficiency, extraction efficiency, and partition coefficient of lutein were 84.64%, 86.73%, and 5.115, respectively, and at this point, the saponification rate of lutein reached 93.98%. Meanwhile, the leaching efficiency, extraction efficiency, and partition coefficient of flavoniods were 96.68%, 78.31%, and 0.2167, respectively. This method shows the superiority to the conventional one for it can not only efficiently extract lutein in marigold flower, but also achieve a high saponification rate of lutein esters and simultaneously separate two major pigments. © 2016 Taylor & Francis.

Wang T.,Jiangsu University | Zhang D.,Yancheng Entry Exit Inspection and Quarantine Bureau | Cai Y.,Jiangsu University | Han J.,Jiangsu University | And 2 more authors.
Journal of Chemical and Engineering Data | Year: 2016

Binodal data for the 1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim]BF4) + salt (MgCl2/Na2WO4) + H2O systems were experimentally determined at T = (288.15, 298.15, and 308.15) K, respectively. The binodal data were successfully correlated by an empirical equation with four parameters. The liquid-liquid equilibrium data were given and satisfactorily correlated by the Othmer-Tobias and Bancroft equations, as well as a two-parameter equation. Additionally, the Chen-NRTL model, the Pitzer-Debye-Hückel equation, and the Flory-Huggins equation were used to determine and correlate the liquid-liquid equilibrium data for the studied systems, and good agreement was obtained with these thermodynamic models. The influences of the two salts and temperature on the phase equilibrium were investigated. The phase-separation ability of MgCl2 is stronger than that of Na2WO4. As the temperature of the systems decreases, the two-phase region shows an expansion trend. © 2016 American Chemical Society.

Wang Y.,Jiangsu University | Chen H.,Jiangsu University | Han J.,Jiangsu University | Wang L.,Jiangsu University | And 3 more authors.
New Journal of Chemistry | Year: 2015

A new simple cyclic non-ligand dual-cloud point extraction (NL-DCPE) pretreatment method through pH regulation coupled with flame atomic absorption spectrometry (FAAS) for the analysis of trace cadmium(ii) was developed. In NL-DCPE, the cloud point process was carried out twice. First, Cd(ii) was extracted into the thermosensitive triblock copolymer L31-rich phase in the form of Cd(OH)2 at pH 13.33, leaving the hydrophilic impurities behind in the aqueous phase. Second, the hydroxide dissociated at pH 3.05 and Cd(ii) was back-extracted into the aqueous phase in the form of Cd2+, thereby discarding the hydrophobic impurities in the L31-rich phase. The L31-rich phase was recycled, and the extraction efficiency could reach up to 90%. Under the optimum conditions, the preconcentration of a 10 mL sample solution could achieve an enrichment factor of 29 and an extraction efficiency of 96.3%. The relative standard deviation (RSD) for six replicate determinations was 4.5%. The method was applied to the determination of trace Cd(ii) in food and environmental samples, and the range of recoveries were 90-102.5%. NL-DCPE successfully achieved the selective separation of the analytes and avoided the interference of the surfactant on the instrument analysis. This method had distinct advantages of simplicity, efficiency, economy and environmental protection, and also has great potential for the preconcentration and separation of other metal ions. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.

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