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Li X.,Jilin University | Zhou X.,Jilin Entry and Exit Inspection and Quarantine Bureau of China | Mu J.,Jilin Entry and Exit Inspection and Quarantine Bureau of China | Lu L.,Jilin Entry and Exit Inspection and Quarantine Bureau of China | And 3 more authors.
Journal of Chemical and Engineering Data | Year: 2011

We have studied the adsorption of p-aminophenol on poly(aryl ether ketone) containing pendant carboxyl groups (PEK-L). The pH effect, adsorption kinetics, isotherms, and thermodynamics are investigated in batch experiments. The kinetics of the adsorption follows a pseudosecond-order model. Langmuir and Freundlich isotherms are employed to describe the adsorption process, indicating that the former fits the data better. The thermodynamic functions, ΔG°, ΔH°, and ΔS° are calculated. The method is applied to the determination of p-aminophenol in drug tablet samples, and the accuracy is assessed through recovery experiments. © 2011 American Chemical Society.

Su R.,Jilin University | Liu Q.,Jilin University | Fan S.,Jilin University | Ma H.,Jilin University | And 2 more authors.
Food Analytical Methods | Year: 2012

A simple and sensitive method based on polymer monolith microextraction (PMME) using a poly(methacrylic acid-co-ethylene glycol dimethacrylate) (poly(MAA-EGDMA)) monolith has been developed for the determination of triazines combined with high-performance liquid chromatography. The method is evaluated with several parameters including linear range, limits of detection, limits of quantification, and reproducibility after optimizing PMME experimental conditions. Sample flow rate, sample volume, eluent flow rate, and sample pH have been investigated and optimized in detail with respect to extraction efficiency of the target compounds from cereal samples. Good linearities are obtained for six triazines with the correlation coefficients (R 2) above 0. 9977. Limits of detection based on three times of standard deviations of blank by seven replicates are in the range of 1. 1-2. 8 μg kg -1. Good reproducibility of the method is obtained, yielding the intra-day and inter-day relative standard deviations less than 4. 3% and 5. 5%, respectively. The method has been proved to be efficient, fast, and sensitive for the quantitative analysis of triazines in practical cereal samples. © 2011 Springer Science+Business Media, LLC.

Ma H.,Jilin University | Mu F.,Jilin University | Fan S.,Jilin University | Zhou X.,Jilin Entry and Exit Inspection and Quarantine Bureau of China | Jia Q.,Jilin University
Journal of Separation Science | Year: 2012

A method based on ultrasound-assisted cloud point extraction (CPE) was developed for the determination of phenolic compounds in water samples by high-performance liquid chromatography coupled with diode array detection (DAD) (HPLC-DAD). A nonionic surfactant, Tergitol 15-S-7, was chosen as the surfactant. The parameters affecting the CPE efficiency, such as Tergitol 15-S-7 concentration, salt concentration, extraction temperature, incubation time, centrifugation time, ultrasonic time, sample pH, and dilution solvent were systematically evaluated and optimized. Under the optimum experimental conditions, the linear regression coefficients of the standard curves were greater than 0.9986 and the limits of detection were in the range of 1.7-6.0 μg/L. The method was shown to be reproducible and reliable with intraday and interday relative standard deviations lower than 4.0 and 5.8%, respectively. The recoveries for the addition of different concentrations of phenolic compounds to water samples were in the range of 81.1-109.4%. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Li W.-J.,Jilin University | Zhou X.,Jilin Entry and Exit Inspection and Quarantine Bureau of China | Tong S.-S.,Jilin University | Jia Q.,Jilin University
Talanta | Year: 2013

The present work proposes a study of the synthesis of poly(N- isopropylacrylamide-co-N,N′-methylene bisacrylamide) monolithic column embedded with γ-alumina nanoparticles and its applications to the extraction of synthetic food dyes in soft drink samples. The monolithic column was synthesized inside fused silica capillaries using thermally initiated free-radical polymerization with N-isopropylacrylamide (NIPAAm) as the monomer, N,N′-methylene bisacrylamide (MBAAm) as the cross-linker, dimethylsulfoxide (DMSO) and dodecanol as the porogen. γ-Alumina nanoparticles were introduced to prevent the swelling of the organic polymer and enhance the loading capacity. In order to obtain optimum experimental conditions, sample pH, sample flow rate, sample volume, eluent flow rate were investigated. Under the optimum conditions, we obtained acceptable linearities, low limits of detection, and good intra-day/inter-day relative standard deviations. When applied to the determination of four synthetic food dyes (Tartrazine, Sunset Yellow, Allura Red, and Azorubine) in soft drink samples, satisfactory recoveries were obtained in the range of 90.4-109.2%. © 2012 Elsevier B.V. All rights reserved.

Ma T.,Jilin University | Li Z.,Jilin University | Niu Q.,Jilin Entry and Exit Inspection and Quarantine Bureau of China | Li Y.,Jilin University | Zhou W.,Jilin University
Electrophoresis | Year: 2015

In this work, double dispersant-assisted ionic liquid dispersive liquid-liquid microextraction coupled with micellar electrokinetic chromatography was developed to determine four UV filters (benzophenone, 4-hydroxybenzophenone, 2,4-dihydroxybenzophenone, and 2-hydroxy-4-methoxybenzophenone). 1-Hexyl-3-methylimidazolium hexafluorophosphate was used as the extraction solvent. The main novelty of the present work was that acetonitrile-Triton X-114 was used as double disperser solvent. Parameters affected the extraction efficiency were investigated and optimized. Under the optimum conditions, enrichment factors were in the range of 25.3-40.5. The limits of detection and quantitation, calculated at a S/N of three and ten, were 3.9-6.7 ng/mL and 13.0-22.3 ng/mL. The linearity of the method was in the range of 0.02-2 μg/mL for 2, 4-dihydroxybenzophenone and 4-hydroxybenzophenone, 0.01-2 μg/mL for benzophenone and 2-hydroxy-4-methoxybenzophenone, with correlation coefficient (R2) of 0.9984-0.9991. The proposed method was successfully applied to the determination of four benzophenone-type UV filters in six kinds of sunscreen cosmetic products, with yielded relative recoveries ranging from 80.2 to 117.7%. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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