A novel method for the determination of five carbamate pesticides （metolcarb, carbofuran, carbaryl, isoprocard and diethofencard） in water samples was developed by dispersive liquid-liquid microextraction （DLLME） ...A novel method for the determination of five carbamate pesticides （metolcarb, carbofuran, carbaryl, isoprocard and diethofencard） in water samples was developed by dispersive liquid-liquid microextraction （DLLME） coupled with high performance liquid chromatography-diode array detector （HPLC-DAD）. Some experimental parameters that influence the extraction efficiency were studied and optimized to obtain the best extraction results. Under the optimum conditions for the method, the calibration curve was linear in the concentration range from 5 to 1000 ng mL^-1 for all the five carbamate pesticides, with the correlation coefficients （r^2） varying from 0.9984 to 0.9994. Good enrichment factors were achieved ranging from 80 to 177- fold, depending on the compound. The limits of detection （LODs） （S/N = 3） were ranged from 0.1 to 0.5 ng mL^-1. The method has been successfully applied to the analysis of the pesticide residues in environmental water samples.展开更多
Methacrylate-based monolithic column was prepared in fused-silica capillary (80 ′ 0.32 mm i.d.) by in situ polymerizetion reaction using glycidyl methacrylate as monomer;ethylene dimethacrylate as crosslinker;1-propa...Methacrylate-based monolithic column was prepared in fused-silica capillary (80 ′ 0.32 mm i.d.) by in situ polymerizetion reaction using glycidyl methacrylate as monomer;ethylene dimethacrylate as crosslinker;1-propanol, 1,4-butanediol, and water as porogenic solvents. The monolith matrix was modified with trimethylamine to create strong anion exchanger via ring opening reaction of epoxy groups. The morphology of the monolithic column was studied by using Scanning Electron Microscope (SEM). This column had good mechanical stability and permeability. The effects of various mobile phases for separation of inorganic anions were investigated. Iodate, bromate, nitrite, bromide, and nitrate were separated within 11 min using100 mMpotassium chloride as mobile phase and detected at 210 nm. This method showed good precision of retention time, acceptable linearity and good sensitivity. Under the optimum condition, the RSD of the retention time was in the range of 1.09%-1.75% (n = 6). The calibration curve showed linear relationships between the peak area and the concentration. The limits of detection (LOD) and the limits of quantitation (LOQ) were between 0.08-0.18 mM and 0.26-0.61 mM, respectively. This method was applied to the determination of inorganic anions in tap water and ground water samples.展开更多
An amperometric detector based on the chemical modification of Nafion and cobalt(II) hexacyanoferrate(II,III) thin film (Nafion/Co CN Fe) onto a glassy carbon (GC) electrode was firstly developed for the determinati...An amperometric detector based on the chemical modification of Nafion and cobalt(II) hexacyanoferrate(II,III) thin film (Nafion/Co CN Fe) onto a glassy carbon (GC) electrode was firstly developed for the determination of electroinactive cations (Li +, Na +, K +, Rb +, Cs + and NH + 4) in single column ion chromatography. A set of well defined peaks of electroinactive cation was obtained. The relative standard deviations (RSDs) of chromatographic peak height (nA) for these cations were all below 3.8%. The cations were detected conveniently in the linear concentration range of 6.0×10 -6 -5.0×10 -3 mol/L and their correlation coefficients were all above 0.99. The detection limits of the cations were 9.2×10 -6 mol/L for Li +, 3.4×10 -6 mol/L for Na +, 6.3×10 -7 mol/L for K +, 7.8×10 -7 mol/L for Rb +, 6.2×10 -7 mol/L for Cs + and 6.2×10 -6 mol/L for NH + 4, at a signal noise ratio of 3. The method was quick, sensitive, simple and was successfully applied to the analysis of rainwater samples. The electrode was stable for a 2 week period of operation with no evidence of chemical or mechanical deterioration.展开更多
基金supported both by the Natural Science Foundations of Hebei(No.B2008000210)the Scientific Research Foundation of Agricultural University of Hebei.
文摘A novel method for the determination of five carbamate pesticides （metolcarb, carbofuran, carbaryl, isoprocard and diethofencard） in water samples was developed by dispersive liquid-liquid microextraction （DLLME） coupled with high performance liquid chromatography-diode array detector （HPLC-DAD）. Some experimental parameters that influence the extraction efficiency were studied and optimized to obtain the best extraction results. Under the optimum conditions for the method, the calibration curve was linear in the concentration range from 5 to 1000 ng mL^-1 for all the five carbamate pesticides, with the correlation coefficients （r^2） varying from 0.9984 to 0.9994. Good enrichment factors were achieved ranging from 80 to 177- fold, depending on the compound. The limits of detection （LODs） （S/N = 3） were ranged from 0.1 to 0.5 ng mL^-1. The method has been successfully applied to the analysis of the pesticide residues in environmental water samples.
文摘Methacrylate-based monolithic column was prepared in fused-silica capillary (80 ′ 0.32 mm i.d.) by in situ polymerizetion reaction using glycidyl methacrylate as monomer;ethylene dimethacrylate as crosslinker;1-propanol, 1,4-butanediol, and water as porogenic solvents. The monolith matrix was modified with trimethylamine to create strong anion exchanger via ring opening reaction of epoxy groups. The morphology of the monolithic column was studied by using Scanning Electron Microscope (SEM). This column had good mechanical stability and permeability. The effects of various mobile phases for separation of inorganic anions were investigated. Iodate, bromate, nitrite, bromide, and nitrate were separated within 11 min using100 mMpotassium chloride as mobile phase and detected at 210 nm. This method showed good precision of retention time, acceptable linearity and good sensitivity. Under the optimum condition, the RSD of the retention time was in the range of 1.09%-1.75% (n = 6). The calibration curve showed linear relationships between the peak area and the concentration. The limits of detection (LOD) and the limits of quantitation (LOQ) were between 0.08-0.18 mM and 0.26-0.61 mM, respectively. This method was applied to the determination of inorganic anions in tap water and ground water samples.
文摘An amperometric detector based on the chemical modification of Nafion and cobalt(II) hexacyanoferrate(II,III) thin film (Nafion/Co CN Fe) onto a glassy carbon (GC) electrode was firstly developed for the determination of electroinactive cations (Li +, Na +, K +, Rb +, Cs + and NH + 4) in single column ion chromatography. A set of well defined peaks of electroinactive cation was obtained. The relative standard deviations (RSDs) of chromatographic peak height (nA) for these cations were all below 3.8%. The cations were detected conveniently in the linear concentration range of 6.0×10 -6 -5.0×10 -3 mol/L and their correlation coefficients were all above 0.99. The detection limits of the cations were 9.2×10 -6 mol/L for Li +, 3.4×10 -6 mol/L for Na +, 6.3×10 -7 mol/L for K +, 7.8×10 -7 mol/L for Rb +, 6.2×10 -7 mol/L for Cs + and 6.2×10 -6 mol/L for NH + 4, at a signal noise ratio of 3. The method was quick, sensitive, simple and was successfully applied to the analysis of rainwater samples. The electrode was stable for a 2 week period of operation with no evidence of chemical or mechanical deterioration.
