A novel method for on-site determination of trace iron was developed using membrane preconcentration and spectrophotometric detection. Fe（II）-ferrozine complex was reacted with cetyltrimethylammonium bromide （CTAB...A novel method for on-site determination of trace iron was developed using membrane preconcentration and spectrophotometric detection. Fe（II）-ferrozine complex was reacted with cetyltrimethylammonium bromide （CTAB） to form a Fe（II）-ferrozine-CTAB paired compound, which was collected on a membrane by filtration under vacuum. The membrane was immersed in 2 mL of ethanol-nitric acid and the absorbance of the solution measured for quantitative analysis. Various factors affecting the iron collection and determination were investigated. With different sample preconcentration volumes, the range of determination was broadened to 0.5-120 ~tg/L. The detection limit of this method reached 0.19 ktg/L and the recoveries were between 97.2 and 109% when the concentration enrichment was about 45. The relative standard deviation （n = 7） was 1.9% for samples containing 10 ~g/L Fe. Twelve seawater samples were analyzed on-site using the proposed method, and two were also analyzed in inductively coupled plasma mass spectrometry. No significant difference was shown between the two methods by the Student＇s t-test. The method has also been used on-site for iron enrichment experiments with phytoplankton and concluded to be simple, accurate and inexpensive.展开更多
This study examined levels of polycyclic aromatic hydrocarbons (PAHs) in estuarine sediments in Licun (Qingdao, China) by gas chromatography under optimized conditions for sample pretreatment via ultrasonic extraction...This study examined levels of polycyclic aromatic hydrocarbons (PAHs) in estuarine sediments in Licun (Qingdao, China) by gas chromatography under optimized conditions for sample pretreatment via ultrasonic extraction, column chromatography, and thin layer chromatography. Methanol and dichloromethane (DCM)/methanol (2:1, v/v) were used in ultrasonic extraction, and DCM was used as eluate for column chromatography. The developing system consisted of n-hexane and DCM at a ratio of 9:1 (v/v), with DCM as the extraction solvent for PAHs-containing silica gel scraped off the plate. When the spiking level is 100 ng, total recoveries of spiked matrices for four target PAHs (phenanthrene, anthracene, pyrene and chrysene) were 83.7%, 76.4%, 85.8%, and 88.7%, respectively, with relative standard deviation (RSD) between 5.0% and 6.5% (n = 4). When the spiking level is 1000 ng, associated total recoveries were 78.6%, 72.7%, 82.7% and 85.3%, respectively, with RSD between 4.4% and 5.3% (n = 4). The opti-mized method was advantageous for determination of PAHs in complex matrix due to its effective sample purification.展开更多
A new method for determination of trace lead and mercury by hydride generation atomic fluorescence spectrometry （HG-AFS） was established. Lead was determined in the medium of citric acid using potassium ferricyanide...A new method for determination of trace lead and mercury by hydride generation atomic fluorescence spectrometry （HG-AFS） was established. Lead was determined in the medium of citric acid using potassium ferricyanide （K3Fe（CN）6） as oxidant. Ni enhanced the fluorescence signals in this system. Mercury was determined in the medium of nitric acid using mixture of thiourea and ascorbic acid as masking reagent, sodium dioctylsulphosuccinate （SDSS） as enhancing reagent. The working mechanism of the hydride generation of lead and mercury was discussed. Interferences of some coexisting ions were studied systematically and the determination conditions were optimized. Under the optimized conditions, the detection limits of the method were 0.31μg.L^-1 for lead and 0.023 μg·L^-1 for mercury, and the relative standard deviations based on eleven determinations of 5.00 μg·L^-1 standard of Pb and Hg, were 2.6% for Pb and 2.2 % for Hg. This method was applied to the analysis of lead and mercury in four different diameter airborne particles after microwave digestion. Results suggested heavy metal elements easily concentrated in smaller particles.展开更多
A simple and sensitive high performance liquid chromatography-chemical vapour generation-atom fluorescent spectrometry （HPLC-CVG-AFS） method was developed and validated for simultaneous determination mercury species...A simple and sensitive high performance liquid chromatography-chemical vapour generation-atom fluorescent spectrometry （HPLC-CVG-AFS） method was developed and validated for simultaneous determination mercury species in Su-He-Xiang-Wan （SHXW） and in tissues of rats, respectively. The species of mercury were separated by a Venusil MP-C 18 （5μm, 150 mm×4.6 ram） column with the optimized mobile phase containing 5% （w/v） acetonitrile, 0.01 mol/L L-cysteine and 0.06 moL/L ammonium acetate. The tissues of rats were freeze-dried after giving the medicine for 10 d, and then added into the solution containing 10% （w/v） HC1, 1% （w/v） sulfocarbamide and 0.15% （w/v） KC1 for increasing extraction rate. The resolutions of Hg2＋, MeHg and EtHg were 1.5 and 2.9, respectively. The detection limits of Hg2＋, MeHg and EtHg were 2.0, 1.0 and 0.9 ng/mL, respectively. The relative standard deviation （RSD） of inter- and intra-day precisions ranged from 1.56% to 2.86%. The recovery rates of three different adding level were 87%-101% （n=6）, and the RSDs were smaller than 8.2%. The results show that no MeHg and EtHg were detected in rat tissues. Only soluble mercury （Hg2＋） was determined for the mercury species of SHXW in rat tissues.展开更多
[Objective]The aim was to find a way to measure the cholesterol content in deserted oil.[Method]Dual-wavelength spectrophotometry method was used for the determination of cholesterol in edible oil.630 nm and 720 nm we...[Objective]The aim was to find a way to measure the cholesterol content in deserted oil.[Method]Dual-wavelength spectrophotometry method was used for the determination of cholesterol in edible oil.630 nm and 720 nm were set as target band and reference band in this method,respectively.The result was compared to liquid chromatography method.[Result]The relative standard deviation(RSD)was at 1.26% and recovery was between 101.9% and 110.7%.Linear range was 8.0-40.0 μg/ml.The tested result was close to the result of liquid chromatography.[Conclusion]It was proved that this method was easy,fast and accurate.The disturbance of sitosterol was eliminated without isolation.It can be used for fast identification of the authenticity of waste fat.展开更多
The residual symmetry of the generalized Kaup-Kupershmidt （KKK） equation is obtained from the truncated Painleve expansion and localized to a Lie point symmetry in a prolonged system. New symmetry reduction solution...The residual symmetry of the generalized Kaup-Kupershmidt （KKK） equation is obtained from the truncated Painleve expansion and localized to a Lie point symmetry in a prolonged system. New symmetry reduction solutions of the prolonged system are given by using the standard Lie symmetry method. Frthermore, the gKK equation is proved to integrable in the sense of owning consistent Riecati expansion and some new Bgcklund transformations are given based on this property, from which interaction solutions between soliton and periodic waves are given.展开更多
基金Supported by State Key Laboratory of Marine Environmental Science(MEL)Funds(No.MELRI1001)
文摘A novel method for on-site determination of trace iron was developed using membrane preconcentration and spectrophotometric detection. Fe（II）-ferrozine complex was reacted with cetyltrimethylammonium bromide （CTAB） to form a Fe（II）-ferrozine-CTAB paired compound, which was collected on a membrane by filtration under vacuum. The membrane was immersed in 2 mL of ethanol-nitric acid and the absorbance of the solution measured for quantitative analysis. Various factors affecting the iron collection and determination were investigated. With different sample preconcentration volumes, the range of determination was broadened to 0.5-120 ~tg/L. The detection limit of this method reached 0.19 ktg/L and the recoveries were between 97.2 and 109% when the concentration enrichment was about 45. The relative standard deviation （n = 7） was 1.9% for samples containing 10 ~g/L Fe. Twelve seawater samples were analyzed on-site using the proposed method, and two were also analyzed in inductively coupled plasma mass spectrometry. No significant difference was shown between the two methods by the Student＇s t-test. The method has also been used on-site for iron enrichment experiments with phytoplankton and concluded to be simple, accurate and inexpensive.
基金supported by the National Natural Science Foundation of China (NSFC project 20775074)
文摘This study examined levels of polycyclic aromatic hydrocarbons (PAHs) in estuarine sediments in Licun (Qingdao, China) by gas chromatography under optimized conditions for sample pretreatment via ultrasonic extraction, column chromatography, and thin layer chromatography. Methanol and dichloromethane (DCM)/methanol (2:1, v/v) were used in ultrasonic extraction, and DCM was used as eluate for column chromatography. The developing system consisted of n-hexane and DCM at a ratio of 9:1 (v/v), with DCM as the extraction solvent for PAHs-containing silica gel scraped off the plate. When the spiking level is 100 ng, total recoveries of spiked matrices for four target PAHs (phenanthrene, anthracene, pyrene and chrysene) were 83.7%, 76.4%, 85.8%, and 88.7%, respectively, with relative standard deviation (RSD) between 5.0% and 6.5% (n = 4). When the spiking level is 1000 ng, associated total recoveries were 78.6%, 72.7%, 82.7% and 85.3%, respectively, with RSD between 4.4% and 5.3% (n = 4). The opti-mized method was advantageous for determination of PAHs in complex matrix due to its effective sample purification.
文摘A new method for determination of trace lead and mercury by hydride generation atomic fluorescence spectrometry （HG-AFS） was established. Lead was determined in the medium of citric acid using potassium ferricyanide （K3Fe（CN）6） as oxidant. Ni enhanced the fluorescence signals in this system. Mercury was determined in the medium of nitric acid using mixture of thiourea and ascorbic acid as masking reagent, sodium dioctylsulphosuccinate （SDSS） as enhancing reagent. The working mechanism of the hydride generation of lead and mercury was discussed. Interferences of some coexisting ions were studied systematically and the determination conditions were optimized. Under the optimized conditions, the detection limits of the method were 0.31μg.L^-1 for lead and 0.023 μg·L^-1 for mercury, and the relative standard deviations based on eleven determinations of 5.00 μg·L^-1 standard of Pb and Hg, were 2.6% for Pb and 2.2 % for Hg. This method was applied to the analysis of lead and mercury in four different diameter airborne particles after microwave digestion. Results suggested heavy metal elements easily concentrated in smaller particles.
基金Projects(20875104, 21075138) supported by the National Natural Science Foundation of China
文摘A simple and sensitive high performance liquid chromatography-chemical vapour generation-atom fluorescent spectrometry （HPLC-CVG-AFS） method was developed and validated for simultaneous determination mercury species in Su-He-Xiang-Wan （SHXW） and in tissues of rats, respectively. The species of mercury were separated by a Venusil MP-C 18 （5μm, 150 mm×4.6 ram） column with the optimized mobile phase containing 5% （w/v） acetonitrile, 0.01 mol/L L-cysteine and 0.06 moL/L ammonium acetate. The tissues of rats were freeze-dried after giving the medicine for 10 d, and then added into the solution containing 10% （w/v） HC1, 1% （w/v） sulfocarbamide and 0.15% （w/v） KC1 for increasing extraction rate. The resolutions of Hg2＋, MeHg and EtHg were 1.5 and 2.9, respectively. The detection limits of Hg2＋, MeHg and EtHg were 2.0, 1.0 and 0.9 ng/mL, respectively. The relative standard deviation （RSD） of inter- and intra-day precisions ranged from 1.56% to 2.86%. The recovery rates of three different adding level were 87%-101% （n=6）, and the RSDs were smaller than 8.2%. The results show that no MeHg and EtHg were detected in rat tissues. Only soluble mercury （Hg2＋） was determined for the mercury species of SHXW in rat tissues.
基金Supported by National Quality Inspection Bureau(KJ092102,2009QK146)
文摘[Objective]The aim was to find a way to measure the cholesterol content in deserted oil.[Method]Dual-wavelength spectrophotometry method was used for the determination of cholesterol in edible oil.630 nm and 720 nm were set as target band and reference band in this method,respectively.The result was compared to liquid chromatography method.[Result]The relative standard deviation(RSD)was at 1.26% and recovery was between 101.9% and 110.7%.Linear range was 8.0-40.0 μg/ml.The tested result was close to the result of liquid chromatography.[Conclusion]It was proved that this method was easy,fast and accurate.The disturbance of sitosterol was eliminated without isolation.It can be used for fast identification of the authenticity of waste fat.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11405110,11275129,11472177the Natural Science Foundation of Zhejiang Province of China under Grant Nos.LY18A050001 and LQ13A050002
文摘The residual symmetry of the generalized Kaup-Kupershmidt （KKK） equation is obtained from the truncated Painleve expansion and localized to a Lie point symmetry in a prolonged system. New symmetry reduction solutions of the prolonged system are given by using the standard Lie symmetry method. Frthermore, the gKK equation is proved to integrable in the sense of owning consistent Riecati expansion and some new Bgcklund transformations are given based on this property, from which interaction solutions between soliton and periodic waves are given.
