The phenomena of molecular adsorption in the nanometer are significant to the research of biological and medical materials, bio-medical engineering and other fields. As
In this study, salting-out assisted liquid-liquid extraction combined with high performance liquid chromatography diode array detector (SALLE-HPLC-DAD) method was developed and validated for simultaneous analysis of c...In this study, salting-out assisted liquid-liquid extraction combined with high performance liquid chromatography diode array detector (SALLE-HPLC-DAD) method was developed and validated for simultaneous analysis of carbaryl, atrazine, propazine, chlorothalonil, dimethametryn and terbutryn in environmental water samples. Parameters affecting the extraction efficiency such as type and volume of extraction solvent, sample volume, salt type and amount, centrifugation speed and time, and sample pH were optimized. Under the optimum extraction conditions the method was linear over the range of 10 - 100 μg/L (carbaryl), 8 - 100 μg/L (atarzine), 7 - 100 μg/L (propazine) and 9 - 100 μg/L (chlorothalonil, terbutryn and dimethametryn) with correlation coefficients (R2) between 0.99 and 0.999. Limits of detection and quantification ranged from 2.0 to 2.8 μg/L and 6.7 to 9.5 μg/L, respectively. The extraction recoveries obtained for ground, lake and river waters were in a range of 75.5% to 106.6%, with the intra-day and inter-day relative standard deviation lower than 3.4% for all the target analytes. All of the target analytes were not detected in these samples. Therefore, the proposed SALLE-HPLC-DAD method is simple, rapid, cheap and environmentally friendly for the determination of the aforementioned herbicides, insecticide and fungicide residues in environmental water samples.展开更多
A new method for the determination of cobalt was developed by dispersive liquid-liquid microextraction preconcentra-tion and flame atomic absorption spectrometry. In the proposed approach, 1,5-bis(di-2-pyridyl) methyl...A new method for the determination of cobalt was developed by dispersive liquid-liquid microextraction preconcentra-tion and flame atomic absorption spectrometry. In the proposed approach, 1,5-bis(di-2-pyridyl) methylene thiocarbohydrazide (DPTH) was used as a chelating agent, and chloroform and ethanol were selected as extraction and dispersive solvents. Some factors influencing the extraction efficiency of cobalt and its subsequent determination, including extraction and dispersive solvent type and volume, pH of sample solution, concentration of the chelating agent, and extraction time, were studied and optimized. Under the optimum conditions, a preconcentration factor of 8 was reached. The detection limit for cobalt was 12.4 ng?mL–1, and the relative standard deviation (RSD) was 3.42% (n = 7, c = 100 ng?mL–1). The method was successfully applied to the determination of cobalt in food, environmental and water samples.展开更多
A method for determination of 226Ra and 228Ra in environmental samples using the α-β coincidence liquid scintillation counting (LSC) has been developed. Radium were preconcentrated from environmental samples by copr...A method for determination of 226Ra and 228Ra in environmental samples using the α-β coincidence liquid scintillation counting (LSC) has been developed. Radium were preconcentrated from environmental samples by coprecipitation with BaSO4, then purified from others radionuclide interferences using the cation column exchange (Bio-Rad AG 50 W-X4 resin with 200-400 mesh size and H+ form) and operating in warm temperature which is between 70-80oC. Then, the Ba(Ra)SO4 precipitate was filtered through the Millipore filter paper, dried and weighed to calculate chemical yield. The activity concentration of radium isotopes in mixture of liquid scintillation cocktails were measured using LSC after being stored for over 21 days to allow the growth of the progeny nuclides. The method has been validated with a certi-fied reference material supplied by the International Atomic Energy Agency and reliable results were obtained. The radiochemical yields for radium were 59% - 90% and recovery was 97% and 80% for 226Ra and 228Ra, respectively. Sixteen seawater and fish flesh samples collected in Kapar coastal water have been analyzed with the developed method. The obtained radium activity concentrations in seawater were in the range of 02.08 ± 0.82 mBq/L to 3.69 ± 1.29 mBq/L for 226Ra and 6.01 ± 3.05 mBq/L to 17.07 ± 6.62 mBq/L for 228Ra. Meanwhile, the activity concentrations of 226Ra and 228Ra in fish flesh were in the range of 11.82 ± 5.23 – 16.53 ± 6.53 Bq/kg dry wt. and 43.52 ± 16.34 – 53.57 ± 19.86 Bq/kg dry wt., respectively.展开更多
A method of rapidly detecting three kinds of microcystins( MCs) in environmental water samples by using disk SPE- ultra high performance liquid chromatography- tandem mass spectrometry( UPLC- MS / MS) was established....A method of rapidly detecting three kinds of microcystins( MCs) in environmental water samples by using disk SPE- ultra high performance liquid chromatography- tandem mass spectrometry( UPLC- MS / MS) was established. Firstly,environmental water samples were extracted by disk SPE column( C_(18)),and three kinds of MCs were separated by Waters BEH C_(18) chromatographic column with acetonitrile- 0. 2% formic acid solution as the mobile phase. After the gradient elution separation,the external standard method was used for quantitative and qualitative analysis under MRM of UPLC- MS / MS. The results showed that the three kinds of MCs in the range of 0. 05- 10 μg / L showed good linear relation,and the correlation coefficients were higher than 0. 999 4,while the method detection limit was 0. 04 ng / L. Under 0. 1,1,and 5 μg / L standard addition for the same environmental sample,the average recovery was 82. 8%- 108. 8%,and the relative standard deviation of determination results was2. 1%- 10. 1%( n = 6). This method is rapid,sensitive and accurate,so it can be effectively applied in the monitoring of MCs in environmental water samples.展开更多
基于膜式固相萃取法和液相色谱-串联质谱法建立了一种高灵敏、快速分析环境水样中痕量全氟化合物(PFASs)的方法。采用最优条件的模式固相萃取进行样品前处理,以乙酸铵水溶液及乙腈为流动相进行梯度洗脱,经Accucore aQ C18色谱柱分离,采...基于膜式固相萃取法和液相色谱-串联质谱法建立了一种高灵敏、快速分析环境水样中痕量全氟化合物(PFASs)的方法。采用最优条件的模式固相萃取进行样品前处理,以乙酸铵水溶液及乙腈为流动相进行梯度洗脱,经Accucore aQ C18色谱柱分离,采用电喷雾离子源、负离子采集模式和质谱多反应监测模式分析,实现了环境水样中17种全氟化合物的快速分析,17种全氟化合物检出限(S/N=3)为0.2~0.3 ng/L。将方法应用于实际环境水样中全氟化合物的分析,加标回收率为87%~95%。研究可为快速、有效地检测环境水样中痕量全氟化合物提供新方法的选择。展开更多
文摘The phenomena of molecular adsorption in the nanometer are significant to the research of biological and medical materials, bio-medical engineering and other fields. As
文摘In this study, salting-out assisted liquid-liquid extraction combined with high performance liquid chromatography diode array detector (SALLE-HPLC-DAD) method was developed and validated for simultaneous analysis of carbaryl, atrazine, propazine, chlorothalonil, dimethametryn and terbutryn in environmental water samples. Parameters affecting the extraction efficiency such as type and volume of extraction solvent, sample volume, salt type and amount, centrifugation speed and time, and sample pH were optimized. Under the optimum extraction conditions the method was linear over the range of 10 - 100 μg/L (carbaryl), 8 - 100 μg/L (atarzine), 7 - 100 μg/L (propazine) and 9 - 100 μg/L (chlorothalonil, terbutryn and dimethametryn) with correlation coefficients (R2) between 0.99 and 0.999. Limits of detection and quantification ranged from 2.0 to 2.8 μg/L and 6.7 to 9.5 μg/L, respectively. The extraction recoveries obtained for ground, lake and river waters were in a range of 75.5% to 106.6%, with the intra-day and inter-day relative standard deviation lower than 3.4% for all the target analytes. All of the target analytes were not detected in these samples. Therefore, the proposed SALLE-HPLC-DAD method is simple, rapid, cheap and environmentally friendly for the determination of the aforementioned herbicides, insecticide and fungicide residues in environmental water samples.
文摘A new method for the determination of cobalt was developed by dispersive liquid-liquid microextraction preconcentra-tion and flame atomic absorption spectrometry. In the proposed approach, 1,5-bis(di-2-pyridyl) methylene thiocarbohydrazide (DPTH) was used as a chelating agent, and chloroform and ethanol were selected as extraction and dispersive solvents. Some factors influencing the extraction efficiency of cobalt and its subsequent determination, including extraction and dispersive solvent type and volume, pH of sample solution, concentration of the chelating agent, and extraction time, were studied and optimized. Under the optimum conditions, a preconcentration factor of 8 was reached. The detection limit for cobalt was 12.4 ng?mL–1, and the relative standard deviation (RSD) was 3.42% (n = 7, c = 100 ng?mL–1). The method was successfully applied to the determination of cobalt in food, environmental and water samples.
文摘A method for determination of 226Ra and 228Ra in environmental samples using the α-β coincidence liquid scintillation counting (LSC) has been developed. Radium were preconcentrated from environmental samples by coprecipitation with BaSO4, then purified from others radionuclide interferences using the cation column exchange (Bio-Rad AG 50 W-X4 resin with 200-400 mesh size and H+ form) and operating in warm temperature which is between 70-80oC. Then, the Ba(Ra)SO4 precipitate was filtered through the Millipore filter paper, dried and weighed to calculate chemical yield. The activity concentration of radium isotopes in mixture of liquid scintillation cocktails were measured using LSC after being stored for over 21 days to allow the growth of the progeny nuclides. The method has been validated with a certi-fied reference material supplied by the International Atomic Energy Agency and reliable results were obtained. The radiochemical yields for radium were 59% - 90% and recovery was 97% and 80% for 226Ra and 228Ra, respectively. Sixteen seawater and fish flesh samples collected in Kapar coastal water have been analyzed with the developed method. The obtained radium activity concentrations in seawater were in the range of 02.08 ± 0.82 mBq/L to 3.69 ± 1.29 mBq/L for 226Ra and 6.01 ± 3.05 mBq/L to 17.07 ± 6.62 mBq/L for 228Ra. Meanwhile, the activity concentrations of 226Ra and 228Ra in fish flesh were in the range of 11.82 ± 5.23 – 16.53 ± 6.53 Bq/kg dry wt. and 43.52 ± 16.34 – 53.57 ± 19.86 Bq/kg dry wt., respectively.
文摘A method of rapidly detecting three kinds of microcystins( MCs) in environmental water samples by using disk SPE- ultra high performance liquid chromatography- tandem mass spectrometry( UPLC- MS / MS) was established. Firstly,environmental water samples were extracted by disk SPE column( C_(18)),and three kinds of MCs were separated by Waters BEH C_(18) chromatographic column with acetonitrile- 0. 2% formic acid solution as the mobile phase. After the gradient elution separation,the external standard method was used for quantitative and qualitative analysis under MRM of UPLC- MS / MS. The results showed that the three kinds of MCs in the range of 0. 05- 10 μg / L showed good linear relation,and the correlation coefficients were higher than 0. 999 4,while the method detection limit was 0. 04 ng / L. Under 0. 1,1,and 5 μg / L standard addition for the same environmental sample,the average recovery was 82. 8%- 108. 8%,and the relative standard deviation of determination results was2. 1%- 10. 1%( n = 6). This method is rapid,sensitive and accurate,so it can be effectively applied in the monitoring of MCs in environmental water samples.
文摘基于膜式固相萃取法和液相色谱-串联质谱法建立了一种高灵敏、快速分析环境水样中痕量全氟化合物(PFASs)的方法。采用最优条件的模式固相萃取进行样品前处理,以乙酸铵水溶液及乙腈为流动相进行梯度洗脱,经Accucore aQ C18色谱柱分离,采用电喷雾离子源、负离子采集模式和质谱多反应监测模式分析,实现了环境水样中17种全氟化合物的快速分析,17种全氟化合物检出限(S/N=3)为0.2~0.3 ng/L。将方法应用于实际环境水样中全氟化合物的分析,加标回收率为87%~95%。研究可为快速、有效地检测环境水样中痕量全氟化合物提供新方法的选择。
