Publications (49)98.55 Total impact
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Article: Fabrication of magnetic microsphere-confined graphene for the preconcentration of some phthalate esters from environmental water and soybean milk samples followed by their determination by HPLC.
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ABSTRACT: In this study, a magnetic microsphere-confined graphene (Fe3O4@SiO2-G) was prepared as a novel adsorbent for the preconcentration of some phthalate esters in environmental water and soybean milk samples prior to high performance liquid chromatography analysis. The properties and morphology of the Fe3O4@SiO2-G were characterized by transmission electron microscopy and X-ray diffraction. This novel graphene-based magnetic nanocomposite showed great adsorptive ability toward the analytes. The method, which takes the advantages of both the high adsorption capacity of G and easy phase separation of the magnetic adsorbent from the sample solution, could avoid the time-consuming experimental procedures related to the traditional solid phase extraction. Various experimental parameters that could affect the extraction efficiencies, such as the amount of Fe3O4@SiO2-G, the extraction time, the pH of sample solution and the desorption conditions, were investigated. Under the optimum conditions, the limits of detection (S/N=3) of the method for the compounds were between 0.07 and 0.10ngmL(-1) in water samples, and between 0.15 and 0.30ngmL(-1) in soybean milk samples. The relative standard deviations (RSDs) varied from 2.7% to 6.1% (n=5). The recoveries of the method were in the range between 87.2% and 109.0% for environmental water and soybean milk samples. The method is suitable to determine the five phthalate esters (diallyl phthalate, di-n-propyl-phthalate, benzyl butyl phthalate, dicyclohexyl-phthalate and diethyl-hexyl-phthalate) in environmental water and soybean milk samples.Talanta 05/2013; 109:133-40. · 3.79 Impact Factor -
Article: Magnetic microsphere-confined graphene for the extraction of polycyclic aromatic hydrocarbons from environmental water samples coupled with high performance liquid chromatography-fluorescence analysis.
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ABSTRACT: In this paper, a magnetic microsphere-confined graphene adsorbent (Fe3O4@SiO2-G) was fabricated and used for the extraction of five polycyclic aromatic hydrocarbons (fluorene, anthracene, phenanthrene, fluoranthene and pyrene) from environmental water samples prior to high performance liquid chromatography with fluorescence detection. The Fe3O4@SiO2-G was characterized by various instrumental methods. Various experimental parameters that could affect the extraction efficiencies, such as the amount of Fe3O4@SiO2-G, the pH and ionic strength of sample solution, the extraction time and the desorption conditions, were investigated. Due to the high surface area and excellent adsorption capacity of the Fe3O4@SiO2-G, satisfactory extraction can be achieved with only 15mg of the adsorbent per 250mL solution and 5min extraction. Under the optimum conditions, a linear response was observed in the concentration range of 5-1500ngL(-1) for fluorene, 2.5-1500ngL(-1) for anthracene and 15-1500ngL(-1) for phenanthrene, fluoranthene and pyrene, with the correlation coefficients (r) ranging from 0.9897 to 0.9961. The limits of detection (S/N=3) of the method were between 0.5 and 5.0ngL(-1). The relative standard deviations (RSDs) were less than 5.6%. The recoveries of the method were in the range between 83.2% and 108.2%. The results indicated that this graphene-based magnetic nanocomposite had a great adsorptive ability toward the five polycyclic aromatic hydrocarbons from environmental water samples.Journal of chromatography. A 04/2013; · 4.19 Impact Factor -
Article: On-line sample concentration and determination of cationic alkaloids in human plasma by micelle to solvent stacking in capillary zone electrophoresis.
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ABSTRACT: A sensitive method for the determination of three cationic alkaloids (berberine, palmatine and jatrorrhizine) from human plasma samples was developed by micelle to solvent stacking (MSS) in capillary zone electrophoresis (CZE). In MSS, the sample preconcentration mainly relies on the reversal in the effective electrophoretic mobility of the analytes at the boundary zone between the sample and CZE background solution (BGS). Under the optimized conditions, the sensitivity enhancement factors achieved in terms of corrected peak area were in the range from 47 to 53 for the alkaloids. The limits of detection (LODs) (S/N=3) for berberine, palmatine and jatrorrhizine were 0.01, 0.01 and 0.02μg/mL, respectively. The intraday (n=6) and interday repeatabilities (n=12) expressed as the relative standard deviations (RSDs) were less than 6.9% in terms of peak height and less than 7.3% in terms of corrected peak area, respectively. The recoveries of the method for the three alkaloids were in the range of 95.9-101.5% with peak height as the quantitative signal, and 92.6-103.6% with corrected peak area as the quantitative signal, respectively. The MSS-CZE method proved to be suitable for the analysis of the alkaloids in human plasma samples.Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 08/2012; 906:41-7. · 2.78 Impact Factor -
Article: A facile one-pot solvothermal method to produce superparamagnetic graphene-Fe(3)O(4) nanocomposite and its application in the removal of dye from aqueous solution.
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ABSTRACT: A superparamagnetic graphene-Fe(3)O(4) nanocomposite (G/Fe(3)O(4)) was synthesized by a facile one-pot solvothermal method. The nanocomposite G/Fe(3)O(4) prepared by the new method was firstly used as an adsorbent to remove dye for water pollution remediation. In comparison with G/Fe(3)O(4) prepared by the in situ chemical coprecipitation, the newly prepared G/Fe(3)O(4) had a higher adsorption efficiency for the dye. The adsorption characteristics of the nanocomposite adsorbent were examined using the organic dye pararosaniline as the adsorbate. The adsorption kinetics, adsorption capacity of the adsorbent, and the effect of the adsorbent dosage and solution pH on the removal efficiency of pararosaniline were investigated. The adsorption capacity of G/Fe(3)O(4) for pararosaniline was evaluated using the Freundlich and Langmuir adsorption isotherm models. The G/Fe(3)O(4) hybrid composite can be easily manipulated in magnetic field for desired separation, leading to an easy removal of the dye from polluted water. The G/Fe(3)O(4) hybrid composite would have a great potential in removing organic dyes from polluted water.Colloids and surfaces. B, Biointerfaces 06/2012; 101C:210-214. · 2.60 Impact Factor -
Article: Analysis of eight pyrethroids in water samples by liquid–liquid microextraction based on solidification of floating organic droplet combined with gas chromatography
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ABSTRACT: A novel method was developed for the determination of eight pyrethroids in water samples by liquid–liquid microextraction based on solidification of floating organic droplets followed by gas chromatography with electron capture detection. The type and volume of the extraction solvents, extraction time, sample solution temperature, stirring rate and ionic strength were studied and optimized. Under the optimum conditions, enrichment factors ranged from 824 to 1,432, and the limit of detection range from 2.0 to 50ng∙L−1. The calibration graph is linear from 0.15 to 80μg∙L−1 for cyfluthrin, fenvalerate, fluvalinate and deltamethrin, 0.09 to 80μg∙L−1 for fenpropathrin, 0.006 to 80μg∙L−1 for lambda-cyhalothrin, 0.026 to 80μg∙L−1 for permethrin, 0.01 to 80μg∙L−1 for cypermethrin. The correlation coefficients (r) varied from 0.9961 to 0.9988. The method was successfully applied to the determination of pyrethroid pesticide residues in tap water, well water, reservoir water, and river water. Recoveries ranged from 79.0% to 113.6%, and relative standard deviations are between 4.1% and 8.7%. KeywordsPyrethroids-GC-ECD-Water samples-Liquid–liquid microextraction based on solidification of floating organic dropletMicrochimica Acta 04/2012; 171(3):241-247. · 3.03 Impact Factor -
Article: Graphene-coated fiber for solid-phase microextraction of triazine herbicides in water samples.
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ABSTRACT: Graphene is a novel and interesting carbon material that could be used for the separation and purification of some chemical compounds. In this investigation, graphene was used as a novel fiber-coating material for the solid-phase microextraction (SPME) of four triazine herbicides (atrazine, prometon, ametryn and prometryn) in water samples. The main parameters that affect the extraction and desorption efficiencies, such as the extraction time, stirring rate, salt addition, desorption solvent and desorption time, were investigated and optimized. The optimized SPME by graphene-coated fiber coupled with high-performance liquid chromatography-diode array detection (HPLC-DAD) was successfully applied for the determination of the four triazine herbicides in water samples. The linearity of the method was in the range from 0.5 to 200 ng/mL, with the correlation coefficients (r) ranging from 0.9989 to 0.9998. The limits of detection of the method were 0.05-0.2 ng/mL. The relative standard deviations varied from 3.5 to 4.9% (n=5). The recoveries of the triazine herbicides from water samples at spiking levels of 20.0 and 50.0 ng/mL were in the range between 86.0 and 94.6%. Compared with two commercial fibers (CW/TPR, 50 μm; PDMS/DVB, 60 μm), the graphene-coated fiber showed higher extraction efficiency.Journal of Separation Science 12/2011; · 2.73 Impact Factor -
Article: Determination of triazine herbicides in environmental water samples by high-performance liquid chromatography using graphene-coated magnetic nanoparticles as adsorbent.
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ABSTRACT: In this paper, a graphene-based Fe(3)O(4) magnetic nanoparticles (G-Fe(3)O(4) MNPs) was used as the adsorbent for the magnetic solid-phase extraction of some triazine herbicides (atrazine, prometon, propazine and prometryn) in environmental water samples followed by high performance liquid chromatography-diode array detection (HPLC-DAD). After the extraction, the adsorbent can be conveniently separated from the aqueous samples by an external magnet. The main factors influencing the extraction efficiency including the amount of the MNPs, the extraction time, the pH of sample solution, and desorption conditions were studied and optimized. Under the optimized experimental conditions, a good linearity was observed in the range of 0.1-50.0 ng mL(-1) for all the analytes, with the correlation coefficients (r) ranging from 0.9996 to 0.9999. The limits of detection of the method ranged between 0.025 and 0.040 ng mL(-1). Good reproducibility was obtained with the relative standard deviations below 5.2%. The developed method was applied to the analysis of the triazine herbicides in different water samples (lake, river and reservoir). The recoveries of the method were in the range between 89.0% and 96.2%.Analytica chimica acta 12/2011; 708(1-2):155-9. · 4.31 Impact Factor -
Article: Determination of some organophosphorus pesticides in water and watermelon samples by microextraction prior to high-performance liquid chromatography.
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ABSTRACT: A novel method based on simultaneous liquid-liquid microextraction and carbon nanotube reinforced hollow fiber microporous membrane solid-liquid phase microextraction has been developed for the determination of six organophosphorus pesticides, i.e. isocarbophos, phosmet, parathion-methyl, triazophos, fonofos and phoxim, in water and watermelon samples prior to high-performance liquid chromatography (HPLC). Under the optimum conditions, the method shows a good linearity within a range of 1-200 ng/mL for water samples and 5-200 ng/g for watermelon samples, with the correlation coefficients (r) varying from 0.9990 to 0.9997 and 0.9986 to 0.9995, respectively. The limits of detection (LODs) were in the range between 0.1 and 0.3 ng/mL for water samples and between 1.0 and 1.5 ng/g for watermelon samples. The recoveries of the method at spiking levels of 5.0 and 50.0 ng/mL for water samples were between 85.4 and 100.8%, and at spiking levels of 5.0 and 50.0 ng/g for watermelon samples, they were between 82.6 and 92.4%, with the relative standard deviations (RSDs) varying from 4.5-6.9% and 5.2-7.4%, respectively. The results suggested that the developed method represents a simple, low-cost, high analytes preconcentration and excellent sample cleanup procedure for the determination of organophosphorus pesticides in water and watermelon samples.Journal of Separation Science 11/2011; 34(22):3231-9. · 2.73 Impact Factor -
Article: Determination of triazine herbicides in environmental samples by dispersive liquid-liquid microextraction coupled with high performance liquid chromatography.
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ABSTRACT: A simple, rapid, efficient, and environmentally friendly method for the determination of five triazine herbicides in water and soil samples was developed by using dispersive liquid-liquid microextraction (DLLME), coupled with high performance liquid chromatography-diode array detection (HPLC-DAD). The water samples were directly used for DLLME extraction. For soil samples, the target analytes were first extracted by water-methanol (99:1, v/v). In the DLLME extraction method, chloroform was used as an extraction solvent, and acetonitrile as a dispersive solvent. Under the optimum conditions, the enrichment factors of DLLME were in the range between 183-221. The linearity of the method was obtained in the range of 0.5-200 ng/mL for the water sample analysis, and 1-200 ng/g for the soil samples, respectively. The correlation coefficients ranged from 0.9968 to 0.9999. The limits of detection were 0.05-0.1 ng/mL for the water samples, and 0.1-0.2 ng/g for the soil samples. The proposed method has been successfully applied to the analysis of target triazine herbicides (simazin, atrazine, prometon, ametryn, and prometryn) in water and soil samples with satisfactory results.Journal of chromatographic science 10/2011; 49(9):689-94. · 0.88 Impact Factor -
Article: Preparation of a graphene-based magnetic nanocomposite for the extraction of carbamate pesticides from environmental water samples.
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ABSTRACT: A graphene-based magnetic nanocomposite was synthesized and used for the first time as an effective adsorbent for the preconcentration of the five carbamate pesticides (metolcarb, carbofuran, pirimicarb, isoprocarb and diethofencarb) in environmental water samples prior to high performance liquid chromatography-diode array detection. The properties of the magnetic nanocomposite were characterized by scanning electron microscopy and X-ray diffraction. This novel graphene-based magnetic nanocomposite showed great adsorptive ability towards the analytes. The method, which takes the advantages of both nanoparticle adsorption and magnetic phase separation from the sample solution, could avoid some of the time-consuming experimental procedures related to the traditional solid phase extraction. Various experimental parameters that could affect the extraction efficiencies have been investigated. Under the optimum conditions, the enrichment factors of the method for the analytes were in the range from 474 to 868. A linear response was achieved in the concentration range of 0.1-50 ng mL(-1). The limits of detection of the method at a signal to noise ratio of 3 for the pesticides were 0.02-0.04 ng mL(-1). Compared with the dispersive liquid-liquid microextraction and the ultrasound-assisted surfactant-enhanced emulsification microextraction, much higher enrichment factors and sensitivities were achieved with the developed method. The method has been successfully applied for the determination of the carbamate pesticides in environmental water samples.Journal of chromatography. A 09/2011; 1218(44):7936-42. · 4.19 Impact Factor -
Article: [Determination of serum proteins by resonance light scattering method with lidocaine as a probe].
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ABSTRACT: A new method for the determination of bovine serum albumin (BSA) and human serum albumin (HSA) was developed by using resonance light scattering (RLS) technique via an interaction of serum albumin with lidocaine and sodium dodecylbenzene sulphonate (SDBS). The RLS intensity of serum albumin was enhanced in the presence of lidocaine and SDBS. The influences of some experimental factors, including incubation time, addition sequence of reagents, pH values, foreign substances and the concentrations of lidocaine and SDBS, on the enhancement of the RLS intensity were investigated. Under the optimal conditions, the enhanced RLS intensities were proportional to the concentrations of serum albumin in the range of 1.0-45.0 mg x L(-1) for BSA and 0.5-30.0 mg x L(-1) for HSA. The method was successfully applied to the determination of real human serum samples, with the relative standard deviations of 4.9%-5.7% (n = 5) and standard addition recoveries of 90%-103%. The method only involves the use of conventional fluorescence spectrometer and chemical reagents. It is simple, easy to operate and sensitive with the limit of detection of 0.14 mg x L(-1). The fresh human serum samples can be directly analyzed without the need of any prior pretreatment. The method can be a good alternative of choice for the determination of BSA and HSA.Guang pu xue yu guang pu fen xi = Guang pu 09/2011; 31(9):2517-20. · 0.84 Impact Factor -
Article: Determination of some sulfonylurea herbicides in soil by a novel liquid-phase microextraction combined with sweeping micellar electrokinetic chromatography.
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ABSTRACT: A novel method for the determination of five sulfonylurea herbicides in soil was developed by a dispersive solid-phase extraction (DSPE) clean-up followed by dispersive liquid-liquid microextraction (DLLME), prior to sweeping micellar electrokinetic chromatography (MEKC). In the DSPE-DLLME, 10 g of soil sample was first extracted with 10 mL of acetonitrile containing 5% formic acid (pH 3.0). The extract was then cleaned-up by a DSPE with C(18) as sorbent. A 1 mL aliquot of the resulting extract was then added into a centrifuge tube containing 5 mL of water adjusted to pH 2.0 and 60.0 μL chlorobenzene (as extraction solvent) for DLLME procedure. Then, the organic sample extraction solution was evaporated to dryness, and reconstituted with 20.0 μL of 1.0 mmol L(-1) Na(2)HPO(4) (pH 10.0) for sweeping-MEKC analysis after DLLME. Under optimized conditions, the method provided as high as 3,000- to 5,000-fold enrichments factors. The linearity of the method was in the range of 3.3-200 ng g(-1) for chlorimuron ethyl and bensulfuron methyl, and in the range of 1.7-200 ng g(-1) for tribenuron methyl, chlorsulfuron and metsulfuron methyl, with the correlation coefficients (r) ranging from 0.9965 to 0.9983, respectively. The limits of detection (LODs) ranged from 0.5 to 1.0 ng g(-1). The intraday relative standard deviations (RSDs, n = 5) were below 5.3% and interday RSDs (n = 15) within 6.8%. The recoveries of the method for the five sulfonylureas from soil samples at spiking levels of 5.0, 20.0, and 100.0 ng g(-1) were 76.0-93.5%, respectively. The developed method has been successfully applied to the analysis of the target sulfonylurea herbicide residues in soil samples with a satisfactory result.Analytical and Bioanalytical Chemistry 06/2011; 401(3):1071-81. · 3.78 Impact Factor -
Article: [Research developments for the applications of carbon nanotubes in separation science].
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ABSTRACT: As a novel nanomaterial, carbon nanotubes (CNTs) have been extensively applied in many fields such as material, catalysis, adsorption and separation, etc. The applications of CNTs in separation science, such as in solid phase extraction (SPE), solid phase microextraction (SPME) and membrane extraction, and as stationary phase for chromatographic separation and capillary electrophoresis (CE) are reviewed in the paper.Se pu = Chinese journal of chromatography / Zhongguo hua xue hui 01/2011; 29(1):6-14. -
Article: Application of ultrasound-assisted surfactant-enhanced emulsification microextraction for the determination of some organophosphorus pesticides in water samples.
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ABSTRACT: An ultrasound-assisted surfactant-enhanced emulsification microextraction (UASEME) was developed as a new approach for the extraction of organophosphorus pesticides (OPs) in water samples prior to high-performance liquid chromatography with diode array detection (HPLC-DAD). The use of a surfactant as an emulsifier in the UASEME method could enhance the dispersion of water-immiscible extraction solvent into aqueous phase and is favorable for the mass-transfer of the analytes from aqueous phase to the organic phase. Several variables that affect the extraction efficiency, including the kind and volume of the extraction solvent, the type and concentration of the surfactant, salt addition, ultrasound emulsification time and temperature, were investigated and optimized. Under the optimum experimental conditions, the calibration curve was linear in the concentration range from 1 to 200 ng mL(-1) for the seven OPs (isocarbophos, phosmet, parathion, parathion-methyl, fenitrothion, fonofos and phoxim), with the correlation coefficients (r) varying from 0.9973 to 0.9998. High enrichment factors were achieved ranging from 210 to 242. The established UASEME-HPLC-DAD method has been successfully applied for the determination of the OPs in real water samples. The limits of detection were in the range between 0.1 and 0.3 ng mL(-1). The recoveries of the target analytes over the three spiked concentration levels of the compounds (10, 50, and 100 ng mL(-1), respectively) in rain, reservoir and well water samples were between 83% and 106% with the relative standard deviations varying from 3.3% to 5.6%.Analytica chimica acta 10/2010; 679(1-2):56-62. · 4.31 Impact Factor -
Article: Application of dispersion-solidification liquid-liquid microextraction for the determination of triazole fungicides in environmental water samples by high-performance liquid chromatography.
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ABSTRACT: A simple, rapid and environmentally friendly method has been developed for the determination of four triazole fungicides (myclobutanil, tebuconazole, triadimenol, hexaconazole) in water samples by dispersion-solidification liquid-liquid microextraction coupled with high performance liquid chromatography-diode array detection. Several variables that affect the extraction efficiencies, including the type and volume of the extraction solvent and dispersive solvent, extraction time, effect of pH and salt addition, were investigated and optimized. Under the optimum conditions, the proposed method is sensitive and shows a good linearity within a range of 0.5-200 ng mL(-1), with the correlation coefficients (r) varying from 0.9992 to 0.9998. High enrichment factors were achieved ranging from 190 to 450. The recoveries of the target analytes from water samples at spiking levels of 1.0, 5.0 and 50.0 ng mL(-1) were between 84.8% and 110.2%. The limits of detection (LODs) for the analytes were ranged in 0.06-0.1 ng mL(-1), and the relative standard deviations (RSD) varied from 3.9% to 5.7%. The proposed method has been successfully applied for the determination of the triazole fungicides in real water samples.Journal of hazardous materials 09/2010; 185(1):71-6. · 4.14 Impact Factor -
Article: Dispersive liquid–liquid microextraction combined with high performance liquid chromatography-DAD detection for the determination of sulfonylurea herbicides in water samples
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ABSTRACT: A new method for the determination of four sulfonylurea herbicides (metsulfuron-methyl, chlorsulfuron, bensulfuron-methyl and chlorimuron-ethyl) in water samples was developed by dispersive liquid–liquid microextraction coupled with high performance liquid chromatography-diode array detector. Parameters that affect the extraction efficiency, such as the kind and volume of the extraction and disperser solvent, extraction time and salt addition, were investigated and optimised. Under the optimum conditions, the enrichment factors were in the range between 102 and 216. The linearity of the method was obtained in the range of 1.0–100 ng mL−1 with the correlation coefficients (r) ranging from 0.9982 to 0.9995. The method detection limits were 0.2–0.3 ng mL−1. The proposed method has been successfully applied to the analysis of target sulfonylurea herbicides in river, stream and well water samples with satisfactory results.Intern. J. Environ. Anal. Chem. 09/2010; 90(11):891-902. -
Article: Determination of organophosphorus pesticides in environmental water samples by dispersive liquid-liquid microextraction with solidification of floating organic droplet followed by high-performance liquid chromatography.
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ABSTRACT: A simple dispersive liquid-liquid microextraction based on solidification of floating organic droplet coupled with high-performance liquid chromatography-diode array detection was developed for the determination of five organophosphorus pesticides (OPs) in water samples. In this method, the extraction solvent used is of low density, low toxicity, and proper melting point near room temperature. The extractant droplet could be collected easily by solidifying it in the lower temperature. Some important experimental parameters that affect the extraction efficiencies were optimized. Under the optimum conditions, the calibration curve was linear in the concentration range from 1 to 200 ng mL(-1) for the five OPs (triazophos, parathion, diazinon, phoxim, and parathion-methyl), with the correlation coefficients (r) varying from 0.9991 to 0.9998. High enrichment factors were achieved ranging from 215 to 557. The limits of detection were in the range between 0.1 and 0.3 ng mL(-1). The recoveries of the target analytes from water samples at spiking levels of 5.0 and 50.0 ng mL(-1) were 82.2-98.8% and 83.6-104.0%, respectively. The relative standard deviations fell in the range of 4.4% to 6.3%. The method was suitable for the determination of the OPs in real water samples.Analytical and Bioanalytical Chemistry 07/2010; 397(6):2543-9. · 3.78 Impact Factor -
Article: Ultrasound-assisted surfactant-enhanced emulsification microextraction for the determination of carbamate pesticides in water samples by high performance liquid chromatography.
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ABSTRACT: A novel ultrasound-assisted surfactant-enhanced emulsification microextraction (UASEME) coupled with high performance liquid chromatography-diode array detection has been developed for the extraction and determination of six carbamate pesticides (metolcarb, carbofuran, carbaryl, pirimicarb, isoprocarb and diethofencarb) in water samples. In the UASEME technique, Tween 20 was used as emulsifier, and chlorobenzene and chloroform were used as dual extraction solvent without using any organic dispersive solvent that is normally required in the previously described common dispersive liquid-liquid microextraction method. Parameters that affect the extraction efficiency, such as the kind and volume of the extraction solvent, the type and concentration of the surfactant, ultrasound emulsification time and salt addition, were investigated and optimized for the method. Under the optimum conditions, the enrichment factors were in the range between 170 and 246. The limits of detection of the method were 0.1-0.3 ng mL(-1) and the limits of quantification were between 0.3 and 0.9 ng mL(-1), depending on the compounds. The linearity of the method was obtained in the range of 0.3-200 ng mL(-1) for metolcarb, carbaryl, pirimicarb, and diethofencarb, 0.6-200 ng mL(-1) for carbofuran, and 0.9-200 ng mL(-1) for isoprocarb, with the correlation coefficients (r) ranging from 0.9982 to 0.9998. The relative standard deviations varied from 3.2 to 4.8% (n=5). The recoveries of the method for the six carbamates from water samples at spiking levels of 1.0, 10.0, 50.0 and 100.0 ng mL(-1) were ranged from 81.0 to 97.5%. The proposed UASEME technique has demonstrated to be simple, practical and environmentally friendly for the determination of carbamates residues in river, reservoir and well water samples.Journal of chromatography. A 01/2010; 1217(11):1773-8. · 4.19 Impact Factor -
Article: [Study on the interaction of tetrandrine and bovine serum albumin].
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ABSTRACT: The interaction of tetrandrine with bovine serum albumin was studied by fluorescence spectra and ultra-violet spectra. The results showed that tetrandrine could quench the intrinsic fluorescence of BSA. Both static quenching and non-radiation energy transfer were the main reasons for the fluorescence quenching. The quenching constants K(sv) at different temperatures were determined using Stern-Volmer equation. The K(sv) were 1.26 x 10(4) L x mol(-1) (300 K), 1.17 x 10(4) L x mol(-1) (310 K) and 1.12 x 10(4) L x mol(-1) (320 K). According to the Forster theory of non-radiation energy transfer, the binding distances (r) were 3.24 nm (300 K), 3.31 nm (310 K) and 3.50 nm (320 K). The binding constants (KA) between tetrandrine and BSA (300 K: 1.52 x 10(5) L x mol(-1); 310 K: 2.03 x 10(5) L x mol(-1); 320 K: 2.89 x 10(5) L x mol(-1)) and thermodynamic parameters were also obtained. The thermodynamic parameters indicated that the interaction of tetrandrine and BSA was driven mainly by hydrophobic force. Results of synchronous fluorescence spectrum showed that the binding could cause conformational changes of BSA.Guang pu xue yu guang pu fen xi = Guang pu 11/2009; 29(11):3088-91. · 0.84 Impact Factor -
Article: Dispersive solid-phase extraction followed by dispersive liquid-liquid microextraction for the determination of some sulfonylurea herbicides in soil by high-performance liquid chromatography.
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ABSTRACT: Dispersive solid-phase extraction (DSPE) combined with dispersive liquid-liquid microextraction (DLLME) has been developed as a new approach for the extraction of four sulfonylurea herbicides (metsulfuron-methyl, chlorsulfuron, bensulfuron-methyl and chlorimuron-ethyl) in soil prior to high-performance liquid chromatography with diode array detection (HPLC-DAD). In the DSPE-DLLME, sulfonylurea herbicides were first extracted from soil sample into acetone-0.15 mol L(-1) NaHCO(3) (2:8, v/v). The clean-up of the extract by DSPE was carried out by directly adding C(18) sorbent into the extract solution, followed by shaking and filtration. After the pH of the filtrate was adjusted to 2.0 with 2 mol L(-1) HCl, 60.0 microL chlorobenzene (as extraction solvent) was added into 5.0 mL of it for DLLME procedure (the acetone contained in the solution also acted as dispersive solvent). Under the optimum conditions, the enrichment factors for the compounds were in the range between 102 and 216. The linearity of the method was in the range from 5.0 to 200 ng g(-1) with the correlation coefficients (r) ranging from 0.9967 to 0.9987. The method detection limits were 0.5-1.2 ng g(-1). The relative standard deviations varied from 5.2% to 7.2% (n=5). The relative recoveries of the four sulfonylurea herbicides from soil samples at spiking levels of 6.0, 20.0 and 60.0 ng g(-1) were in the range between 76.3% and 92.5%. The proposed method has been successfully applied to the analysis of the four target sulfonylurea herbicides in soil samples, and a satisfactory result was obtained.Journal of chromatography. A 08/2009; 1216(29):5504-10. · 4.19 Impact Factor
Top co-authors
Top Journals
Institutions
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2008–2012
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Agricultural University Of Hebei
Baoding, Hebei, China
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2006
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University of Alabama at Birmingham
- Department of Pharmacology and Toxicology
Birmingham, AL, USA
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