A rapid method has been developed based on the sample preparation procedure named as QuEChERS （Quick, Easy, Cheap, Effective, Rugged and Safe）, combined with reversed-phase high performance liquid chromatography wit...A rapid method has been developed based on the sample preparation procedure named as QuEChERS （Quick, Easy, Cheap, Effective, Rugged and Safe）, combined with reversed-phase high performance liquid chromatography with fluorescence detector and C18 column after precolumn derivatization using o-phthalaldehyde and 2-mercaptoethanol to determine dopamine in porcine muscle. Methanol and deionized water （0.1% acetic acid, v/v） with a ratio of 60：40 was used as mobile phase. The flow rate was 0.8 mL/min and dopamine was eluted within 15 min. The linearity range was 0.003-8 μg/mL with r=0.9992. The detection limit for dopamine was 4 μg/kg and the quantification limit was 9 μg/kg. Recovery studies were carried out at 0.1, 0.5 and 1.0 mg/kg fortification levels and the average recoveries obtained ranged from 90.4% to 98.2% with relative standard deviations between 3.5% and 8.1%. The method was found to be suitable for detection of dopamine in animal product tissues at the maximum residue level.展开更多
In recent years,engineered nanoparticles,as a new group of contaminants emerging in natural water,have been given more attention AlCl3 In order to understand the behavior of nanoparticles in the conventional water tre...In recent years,engineered nanoparticles,as a new group of contaminants emerging in natural water,have been given more attention AlCl3 In order to understand the behavior of nanoparticles in the conventional water treatment process,three kinds of nanoparticle suspensions,namely multi-walled carbon nanotube-humic acid（MWCNT-HA）,multiwalled carbon nanotube-N,N-dimethylformamide（MWCNT-DMF） and nano TiO2-humic acid（TiO2-HA） were employed to investigate their coagulation removal efficiencies with varying aluminum chloride（AlCl3） concentrations AlCl3 Results showed that nanoparticle removal rate curves had a reverse ＂U＂ shape with increasing concentration of aluminum ion（Al^（3＋） ）AlCl3 More than 90% of nanoparticles could be effectively removed by an appropriate Al^（3＋） concentration AlCl3 At higher Al^（3＋） concentration,nanoparticles would be restabilized AlCl3 The hydrodynamic particle size of nanoparticles was found to be the crucial factor influencing the effective concentration range（ECR） of Al^（3＋） for nanoparticle removal AlCl3 The ECR of Al^（3＋） followed the order MWCNT-DMF 〉 MWCNT-HA 〉 TiO2-HA,which is the reverse of the nanoparticle size trend AlCl3 At a given concentration,smaller nanoparticles carry more surface charges,and thus consume more coagulants for neutralization AlCl3 Therefore,over-saturation occurred at relatively higher Al^（3＋） concentration and a wider ECR was obtained AlCl3 The ECR became broader with increasing p H because of the smaller hydrodynamic particle size of nanoparticles at higher p H values AlCl3 A high ionic strength of Na Cl can also widen the ECR due to its strong potential to compress the electric double layer AlCl3 It was concluded that it is important to adjust the dose of Al^（3＋） in the ECR for nanoparticle removal in water treatment.展开更多
基金supported by the Natural Science Foundation of Shaanxi Province (no.2009jm4002-1)
文摘A rapid method has been developed based on the sample preparation procedure named as QuEChERS （Quick, Easy, Cheap, Effective, Rugged and Safe）, combined with reversed-phase high performance liquid chromatography with fluorescence detector and C18 column after precolumn derivatization using o-phthalaldehyde and 2-mercaptoethanol to determine dopamine in porcine muscle. Methanol and deionized water （0.1% acetic acid, v/v） with a ratio of 60：40 was used as mobile phase. The flow rate was 0.8 mL/min and dopamine was eluted within 15 min. The linearity range was 0.003-8 μg/mL with r=0.9992. The detection limit for dopamine was 4 μg/kg and the quantification limit was 9 μg/kg. Recovery studies were carried out at 0.1, 0.5 and 1.0 mg/kg fortification levels and the average recoveries obtained ranged from 90.4% to 98.2% with relative standard deviations between 3.5% and 8.1%. The method was found to be suitable for detection of dopamine in animal product tissues at the maximum residue level.
基金Financial support from the National Natural Science Foundation of China(No.20802049) and Program for New Century Excellent Talents in University of Tianjin City
基金supported by the Hundreds Talents Program of Chinese Academy of SciencesOpen Foundation of State Key Laboratory of Environmental Criteria and Risk Assessment+1 种基金Chinese Research Academy of Environmental Sciences (SKLECRA2015OFP10)Natural Science Foundation of Heilong Jiang Province
文摘In recent years,engineered nanoparticles,as a new group of contaminants emerging in natural water,have been given more attention AlCl3 In order to understand the behavior of nanoparticles in the conventional water treatment process,three kinds of nanoparticle suspensions,namely multi-walled carbon nanotube-humic acid（MWCNT-HA）,multiwalled carbon nanotube-N,N-dimethylformamide（MWCNT-DMF） and nano TiO2-humic acid（TiO2-HA） were employed to investigate their coagulation removal efficiencies with varying aluminum chloride（AlCl3） concentrations AlCl3 Results showed that nanoparticle removal rate curves had a reverse ＂U＂ shape with increasing concentration of aluminum ion（Al^（3＋） ）AlCl3 More than 90% of nanoparticles could be effectively removed by an appropriate Al^（3＋） concentration AlCl3 At higher Al^（3＋） concentration,nanoparticles would be restabilized AlCl3 The hydrodynamic particle size of nanoparticles was found to be the crucial factor influencing the effective concentration range（ECR） of Al^（3＋） for nanoparticle removal AlCl3 The ECR of Al^（3＋） followed the order MWCNT-DMF 〉 MWCNT-HA 〉 TiO2-HA,which is the reverse of the nanoparticle size trend AlCl3 At a given concentration,smaller nanoparticles carry more surface charges,and thus consume more coagulants for neutralization AlCl3 Therefore,over-saturation occurred at relatively higher Al^（3＋） concentration and a wider ECR was obtained AlCl3 The ECR became broader with increasing p H because of the smaller hydrodynamic particle size of nanoparticles at higher p H values AlCl3 A high ionic strength of Na Cl can also widen the ECR due to its strong potential to compress the electric double layer AlCl3 It was concluded that it is important to adjust the dose of Al^（3＋） in the ECR for nanoparticle removal in water treatment.
