To take advantage of micelle to solvent stacking (MSS) to achieve more sensitivity enhancement with enough selectivity, the application of capillary electrophoretic online sequential concentration based on the MSS was...To take advantage of micelle to solvent stacking (MSS) to achieve more sensitivity enhancement with enough selectivity, the application of capillary electrophoretic online sequential concentration based on the MSS was reviewed. MSS has been coupled to sweeping FASS, FASI and normal EKI. Furthermore, multiple stacking by coupling MSS with more than one stacking method has also been reported. It is more sensitive and selective than solely used of one or two stacking methods and is very suitable for complex and trace sample analysis.展开更多
The unstable state of nitrite results in its very low concentration in seawater, which is below the limit of detection （LOD） of conventional techniques of analysis. Some sensitivity-enhanced methods have been propos...The unstable state of nitrite results in its very low concentration in seawater, which is below the limit of detection （LOD） of conventional techniques of analysis. Some sensitivity-enhanced methods have been proposed for the determination of nitrite at nanomolar level to illustrate the role of nitrite in the marine nitrogen cycle. However, most of previous reports are not widely accepted, because of their complexity and cost equipment or intensive labor requirement. In this study, a simple automatic system for the determination of nanomolar level nitrite using on-line preconcentration with spectrophotometric detection was described..An Oasis HLB cartridge was adopted to quantitatively enrich the pink-colored azo compound, formed from nitrite via Griess reaction. The cartridge was rinsed with water and ethanol （volume fraction is 55%, the same below）, in turn, then eluted by an eluent containing 50% ethanol and 0.25 M（mol/dm^3） H2SO4, and determined at 543 nm with a 2 cm path-length flow cell. Under the optimized experimental conditions, the calibration curve showed a good linearity in the range of 1.4 85.7 aM, and the LOD （3a） was estimated to be 0.5 nM. The relative standard deviations of 7 measurements were 4.0% and 1.0% for the samples spiked at 7.1 and 28.6 nM, respectively. The recoveries for the different natural water samples were between 92.2%-108.4%. Each HLB cartridge could be reused for at least 50 times. As compared with other SPE methods, the advantages of this method included the free of interference from salinity variation and less sample consuming. The results of the application of the proposed method to natural water showed good agreement with liquid waveguide capillary cell detection method.展开更多
A new method for the determination of atrazine, simazine and prometryn in water samples by on-line sweeping concentration technique in micellar electrokinetic chromatography （MEKC） was developed. Various parameters ...A new method for the determination of atrazine, simazine and prometryn in water samples by on-line sweeping concentration technique in micellar electrokinetic chromatography （MEKC） was developed. Various parameters affecting sample enrichment and separation efficiency were systematically studied. Compared with the conventional MEKC method, up to 60-200-fold improvement in concentration sensitivity was achieved in terms of peak height by using this sweeping injection technique. The compound strychnine was used as the internal standard for the improvement of the experimental reproducibility. The limits of detection （S/ N = 3：1） for atrazine, simazine and prometryn were 9, 10 and 0.5 ng mL-1, respectively. This method has been successfully applied to the analysis of atrazine, simazine and prometryn in lake, steam and ground water.展开更多
A sensitive and simple micellar electrokinetic chromatography （MEKC） method was developed for the determination of antiepileptic drug, carbamazepine （CBZ）, using sweeping on-line concentration method with photodio...A sensitive and simple micellar electrokinetic chromatography （MEKC） method was developed for the determination of antiepileptic drug, carbamazepine （CBZ）, using sweeping on-line concentration method with photodiode array detection. Under the optimal conditions, the calibration curve was linear over a range of 0.5-40μg·mL^-1 for CBZ with a correlation coefficient of 0.998. The detection limit （S/N = 3：1） of CBZ was 0.10 μg·mL^-1. The sweeping-MEKC method has been successfully applied to the analysis of CBZ in human serum.展开更多
Identification of the most appropriate chemically extractable pool for evaluating Cd and Pb availability remains elusive,hindering accurate assessment on environmental risks and effectiveness of remediation strategies...Identification of the most appropriate chemically extractable pool for evaluating Cd and Pb availability remains elusive,hindering accurate assessment on environmental risks and effectiveness of remediation strategies.This study evaluated the feasibility of European Community Bureau of Reference(BCR)sequential extraction,Ca(NO_(3))_(2)extraction,and water extraction on assessing Cd and Pb availability in agricultural soil amended with slaked lime,magnesium hydroxide,corn stover biochar,and calcium dihydrogen phosphate.Moreover,the enriched isotope tracing technique(^(112)Cd and^(206)Pb)was employed to evaluate the aging process of newly introduced Cd and Pbwithin 56 days’incubation.Results demonstrated that extractable pools by BCR and Ca(NO_(3))_(2)extraction were little impacted by amendments and showed little correlation with soil pH.This is notable because soil pH is closely linked to metal availability,indicating these extraction methods may not adequately reflect metal availability.Conversely,water-soluble concentrations of Cd and Pb were markedly influenced by amendments and exhibited strong correlations with pH(Pearson’s r:-0.908 to-0.825,P<0.001),suggesting water extraction as a more sensitive approach.Furthermore,newly introduced metals underwent a more evident aging process as demonstrated by acid-soluble and water-soluble pools.Additionally,water-soluble concentrations of essential metals were impacted by soil amendments,raising caution on their potential effects on plant growth.These findings suggest water extraction as a promising and attractive method to evaluate Cd and Pb availability,which will help provide assessment guidance for environmental risks caused by heavy metals and develop efficient remediation strategies.展开更多
Reagents are optimized for the simultaneous determination of trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in zinc sulfate solution, which contains an extremely large excess of Zn^(2+). First, the reagents and their d...Reagents are optimized for the simultaneous determination of trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in zinc sulfate solution, which contains an extremely large excess of Zn^(2+). First, the reagents and their doses for the experiment are selected according to the characteristics of the zinc sulfate solution. Then, the reagent doses are optimized by analyzing the influence of reagent dose on the polarographic parameters(i.e. half-wave potential E_(1/2) and limiting diffusion current I_p). Finally, the optimization results are verified by simultaneously determining trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in the presence of an extremely large excess of Zn^(2+). The determination results indicate that the optimized reagents exhibit wide linearity, low detection limits, high accuracy and good precision for the simultaneous determination of trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in the presence of an extremely large excess of Zn^(2+).展开更多
An on-line forecasting model based on self-tuning support vectors regression for zinc output was put forward to maximize zinc output by adjusting operational parameters in the process of imperial smelting furnace. In ...An on-line forecasting model based on self-tuning support vectors regression for zinc output was put forward to maximize zinc output by adjusting operational parameters in the process of imperial smelting furnace. In this model, the mathematical model of support vector regression was converted into the same format as support vector machine for classification. Then a simplified sequential minimal optimization for classification was applied to train the regression coefficient vector α- α* and threshold b. Sequentially penalty parameter C was tuned dynamically through forecasting result during the training process. Finally, an on-line forecasting algorithm for zinc output was proposed. The simulation result shows that in spite of a relatively small industrial data set, the effective error is less than 10% with a remarkable performance of real time. The model was applied to the optimization operation and fault diagnosis system for imperial smelting furnace.展开更多
On-line detection of additive concentrations in acidic copper(Cu)electroplating solution,including the suppressor,accelerator and leveler,is crucial for the industrial production of integrated circuit metal interconne...On-line detection of additive concentrations in acidic copper(Cu)electroplating solution,including the suppressor,accelerator and leveler,is crucial for the industrial production of integrated circuit metal interconnections.For this purpose,a portable electrochemical microfluidic workstation(EMW)is developed.The polymer electrochemical microfluidic chip is designed and fabricated by 3D printing,in which a liquid mixer is integrated with an electrochemical microcell.The asymmetrically distributed herringbone microstructures in the microchannels(width:400μm,height:300μm,length:4 cm)ensure the highly efficient mixture of solutions.In the electrochemical microcell,a 12.5μm radius platinum ultramicroelectrode(Pt UME)acts as the working electrode.Based on the suppressing or accelerating effects of the additives on Cu electroplating,the calibration curves can be obtained by the stripping charge of electrodeposited Cu.Thus,the concentration of each additive in the acidic Cu electroplating solution can be detected on line and adjusted in time.The solution volume needed for each additive is approximately 220μL.The detection error is lower than 10%,meeting the analytic requirements in industry.The automated EMW has the potential to replace the current manual cyclic voltammetry stripping(CVS)employed in lab analysis.展开更多
针对燃煤电厂参与调峰负荷波动较大,出口SO_(2)浓度控制效果不佳的问题,建立了一种基于捕鱼优化算法(catch fish optimization algorithm,CFOA)优化融合神经网络的出口SO_(2)浓度预测模型。首先使用互信息算法筛选由机理分析得到的特征...针对燃煤电厂参与调峰负荷波动较大,出口SO_(2)浓度控制效果不佳的问题,建立了一种基于捕鱼优化算法(catch fish optimization algorithm,CFOA)优化融合神经网络的出口SO_(2)浓度预测模型。首先使用互信息算法筛选由机理分析得到的特征变量,并通过逐次变分模态分解对筛选后的辅助变量进行分解重构,保留相关性较大的重构分量作为输入变量。随后采用双向时间卷积网络、双向门控循环单元与多头自注意力机制构建融合神经网络模型,通过CFOA对模型超参数寻优以进一步提高精度。最后使用某660 MW燃煤电厂历史运行数据进行对比实验,实验结果表明,该模型在出口SO_(2)浓度剧烈波动的工况下仍能实现较好的预测效果。同多种模型对比,该模型具有更小的误差和更高的预测精度,体现出其在复杂变化环境中的鲁棒性和可靠性。展开更多
Trace of Pb(Ⅱ)has been on-line separated and enriched from environmental samples and wastewater by using the self-made alizarin violet functionalized silica gel micro-column coupling with a sequential injection sampl...Trace of Pb(Ⅱ)has been on-line separated and enriched from environmental samples and wastewater by using the self-made alizarin violet functionalized silica gel micro-column coupling with a sequential injection sampling technology.The determination is based on the color reaction of Pb(Ⅱ)with iodide and crystal violet to form an ionic association complex in the presence of polyvinyl alcohol and hydrochloric acid.The use of the microcolumn can prevent the interference of most familiar metal ions,and therefore improve the selectivity and sensitivity of this analytical technique.The proposed method was used for the determination of Pb(Ⅱ)in environmental samples and wastewater.No statistically significant difference was observed between the results determined by the present method and atomic absorption spectrometry.展开更多
通过LabVIEW软件编译,与FIAlab for Windows软件结合,分别控制光纤光谱仪和微顺序注射-阀上实验室(MicroSIA Lab-on-valve,μSIA-LOV)系统,以光纤作为传导介质,将光纤光谱仪、微顺序注射分析仪和氘灯光源连接,基于样品的紫外吸收特性,...通过LabVIEW软件编译,与FIAlab for Windows软件结合,分别控制光纤光谱仪和微顺序注射-阀上实验室(MicroSIA Lab-on-valve,μSIA-LOV)系统,以光纤作为传导介质,将光纤光谱仪、微顺序注射分析仪和氘灯光源连接,基于样品的紫外吸收特性,实现原位待测样品溶液浓度随时间变化的实时在线监测。编译光谱采集模块,进行样品溶液的光谱扫描,实现对物质的定性分析;编译标准曲线模块,实现对物质的定量分析方法的建立;编译样品检测模块,实现样品溶液浓度的实时连续测定。并以头孢氨苄为例,基于紫外吸收测定模式的LabVIEW软件编译的3个模块,同时对待测样品进行原位和过程分析,与紫外分光光度计测得结果比较(P>0.05),结果无显著性差异。说明LabVIEW软件编译的3个模块可实现待测溶液浓度的原位实时连续监测。展开更多
文摘To take advantage of micelle to solvent stacking (MSS) to achieve more sensitivity enhancement with enough selectivity, the application of capillary electrophoretic online sequential concentration based on the MSS was reviewed. MSS has been coupled to sweeping FASS, FASI and normal EKI. Furthermore, multiple stacking by coupling MSS with more than one stacking method has also been reported. It is more sensitive and selective than solely used of one or two stacking methods and is very suitable for complex and trace sample analysis.
基金The National High Technology Research and Development Program of China under contract Nos 2006AA09Z174 and 2007AA061501the National Natural Science Foundation of China under contract No. 40521003
文摘The unstable state of nitrite results in its very low concentration in seawater, which is below the limit of detection （LOD） of conventional techniques of analysis. Some sensitivity-enhanced methods have been proposed for the determination of nitrite at nanomolar level to illustrate the role of nitrite in the marine nitrogen cycle. However, most of previous reports are not widely accepted, because of their complexity and cost equipment or intensive labor requirement. In this study, a simple automatic system for the determination of nanomolar level nitrite using on-line preconcentration with spectrophotometric detection was described..An Oasis HLB cartridge was adopted to quantitatively enrich the pink-colored azo compound, formed from nitrite via Griess reaction. The cartridge was rinsed with water and ethanol （volume fraction is 55%, the same below）, in turn, then eluted by an eluent containing 50% ethanol and 0.25 M（mol/dm^3） H2SO4, and determined at 543 nm with a 2 cm path-length flow cell. Under the optimized experimental conditions, the calibration curve showed a good linearity in the range of 1.4 85.7 aM, and the LOD （3a） was estimated to be 0.5 nM. The relative standard deviations of 7 measurements were 4.0% and 1.0% for the samples spiked at 7.1 and 28.6 nM, respectively. The recoveries for the different natural water samples were between 92.2%-108.4%. Each HLB cartridge could be reused for at least 50 times. As compared with other SPE methods, the advantages of this method included the free of interference from salinity variation and less sample consuming. The results of the application of the proposed method to natural water showed good agreement with liquid waveguide capillary cell detection method.
基金sponsored by the Natural Science Foundation of Hebei (Nos.B2006000413,B2008000210).
文摘A new method for the determination of atrazine, simazine and prometryn in water samples by on-line sweeping concentration technique in micellar electrokinetic chromatography （MEKC） was developed. Various parameters affecting sample enrichment and separation efficiency were systematically studied. Compared with the conventional MEKC method, up to 60-200-fold improvement in concentration sensitivity was achieved in terms of peak height by using this sweeping injection technique. The compound strychnine was used as the internal standard for the improvement of the experimental reproducibility. The limits of detection （S/ N = 3：1） for atrazine, simazine and prometryn were 9, 10 and 0.5 ng mL-1, respectively. This method has been successfully applied to the analysis of atrazine, simazine and prometryn in lake, steam and ground water.
文摘A sensitive and simple micellar electrokinetic chromatography （MEKC） method was developed for the determination of antiepileptic drug, carbamazepine （CBZ）, using sweeping on-line concentration method with photodiode array detection. Under the optimal conditions, the calibration curve was linear over a range of 0.5-40μg·mL^-1 for CBZ with a correlation coefficient of 0.998. The detection limit （S/N = 3：1） of CBZ was 0.10 μg·mL^-1. The sweeping-MEKC method has been successfully applied to the analysis of CBZ in human serum.
基金supported by the National Natural Science Foundation of Shandong(No.ZR2020ZD20)the National Natural Science Foundation of China(No.22193051)+1 种基金the National Young Top-Notch Talents(No.W03070030)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.Y202011).
文摘Identification of the most appropriate chemically extractable pool for evaluating Cd and Pb availability remains elusive,hindering accurate assessment on environmental risks and effectiveness of remediation strategies.This study evaluated the feasibility of European Community Bureau of Reference(BCR)sequential extraction,Ca(NO_(3))_(2)extraction,and water extraction on assessing Cd and Pb availability in agricultural soil amended with slaked lime,magnesium hydroxide,corn stover biochar,and calcium dihydrogen phosphate.Moreover,the enriched isotope tracing technique(^(112)Cd and^(206)Pb)was employed to evaluate the aging process of newly introduced Cd and Pbwithin 56 days’incubation.Results demonstrated that extractable pools by BCR and Ca(NO_(3))_(2)extraction were little impacted by amendments and showed little correlation with soil pH.This is notable because soil pH is closely linked to metal availability,indicating these extraction methods may not adequately reflect metal availability.Conversely,water-soluble concentrations of Cd and Pb were markedly influenced by amendments and exhibited strong correlations with pH(Pearson’s r:-0.908 to-0.825,P<0.001),suggesting water extraction as a more sensitive approach.Furthermore,newly introduced metals underwent a more evident aging process as demonstrated by acid-soluble and water-soluble pools.Additionally,water-soluble concentrations of essential metals were impacted by soil amendments,raising caution on their potential effects on plant growth.These findings suggest water extraction as a promising and attractive method to evaluate Cd and Pb availability,which will help provide assessment guidance for environmental risks caused by heavy metals and develop efficient remediation strategies.
基金Projects(61533021,61321003,61273185)supported by the National Natural Science Foundation of ChinaProject(2015CX007)supported by the Innovation-driven Plan in Central South University,ChinaProject(13JJ8003)supported by the Joint Fund of Hunan Provincial Natural Science Foundation of China
文摘Reagents are optimized for the simultaneous determination of trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in zinc sulfate solution, which contains an extremely large excess of Zn^(2+). First, the reagents and their doses for the experiment are selected according to the characteristics of the zinc sulfate solution. Then, the reagent doses are optimized by analyzing the influence of reagent dose on the polarographic parameters(i.e. half-wave potential E_(1/2) and limiting diffusion current I_p). Finally, the optimization results are verified by simultaneously determining trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in the presence of an extremely large excess of Zn^(2+). The determination results indicate that the optimized reagents exhibit wide linearity, low detection limits, high accuracy and good precision for the simultaneous determination of trace amounts of Cu^(2+), Cd^(2+) and Co^(2+) in the presence of an extremely large excess of Zn^(2+).
文摘An on-line forecasting model based on self-tuning support vectors regression for zinc output was put forward to maximize zinc output by adjusting operational parameters in the process of imperial smelting furnace. In this model, the mathematical model of support vector regression was converted into the same format as support vector machine for classification. Then a simplified sequential minimal optimization for classification was applied to train the regression coefficient vector α- α* and threshold b. Sequentially penalty parameter C was tuned dynamically through forecasting result during the training process. Finally, an on-line forecasting algorithm for zinc output was proposed. The simulation result shows that in spite of a relatively small industrial data set, the effective error is less than 10% with a remarkable performance of real time. The model was applied to the optimization operation and fault diagnosis system for imperial smelting furnace.
基金the National Natural Science Foundation of China(22132003,22202166)National Key Research and Development Program of China(2023YFF0713900).
文摘On-line detection of additive concentrations in acidic copper(Cu)electroplating solution,including the suppressor,accelerator and leveler,is crucial for the industrial production of integrated circuit metal interconnections.For this purpose,a portable electrochemical microfluidic workstation(EMW)is developed.The polymer electrochemical microfluidic chip is designed and fabricated by 3D printing,in which a liquid mixer is integrated with an electrochemical microcell.The asymmetrically distributed herringbone microstructures in the microchannels(width:400μm,height:300μm,length:4 cm)ensure the highly efficient mixture of solutions.In the electrochemical microcell,a 12.5μm radius platinum ultramicroelectrode(Pt UME)acts as the working electrode.Based on the suppressing or accelerating effects of the additives on Cu electroplating,the calibration curves can be obtained by the stripping charge of electrodeposited Cu.Thus,the concentration of each additive in the acidic Cu electroplating solution can be detected on line and adjusted in time.The solution volume needed for each additive is approximately 220μL.The detection error is lower than 10%,meeting the analytic requirements in industry.The automated EMW has the potential to replace the current manual cyclic voltammetry stripping(CVS)employed in lab analysis.
文摘针对燃煤电厂参与调峰负荷波动较大,出口SO_(2)浓度控制效果不佳的问题,建立了一种基于捕鱼优化算法(catch fish optimization algorithm,CFOA)优化融合神经网络的出口SO_(2)浓度预测模型。首先使用互信息算法筛选由机理分析得到的特征变量,并通过逐次变分模态分解对筛选后的辅助变量进行分解重构,保留相关性较大的重构分量作为输入变量。随后采用双向时间卷积网络、双向门控循环单元与多头自注意力机制构建融合神经网络模型,通过CFOA对模型超参数寻优以进一步提高精度。最后使用某660 MW燃煤电厂历史运行数据进行对比实验,实验结果表明,该模型在出口SO_(2)浓度剧烈波动的工况下仍能实现较好的预测效果。同多种模型对比,该模型具有更小的误差和更高的预测精度,体现出其在复杂变化环境中的鲁棒性和可靠性。
基金supported by the Science and Technology Department of Henan Province(082300423202&102300410194)
文摘Trace of Pb(Ⅱ)has been on-line separated and enriched from environmental samples and wastewater by using the self-made alizarin violet functionalized silica gel micro-column coupling with a sequential injection sampling technology.The determination is based on the color reaction of Pb(Ⅱ)with iodide and crystal violet to form an ionic association complex in the presence of polyvinyl alcohol and hydrochloric acid.The use of the microcolumn can prevent the interference of most familiar metal ions,and therefore improve the selectivity and sensitivity of this analytical technique.The proposed method was used for the determination of Pb(Ⅱ)in environmental samples and wastewater.No statistically significant difference was observed between the results determined by the present method and atomic absorption spectrometry.
文摘通过LabVIEW软件编译,与FIAlab for Windows软件结合,分别控制光纤光谱仪和微顺序注射-阀上实验室(MicroSIA Lab-on-valve,μSIA-LOV)系统,以光纤作为传导介质,将光纤光谱仪、微顺序注射分析仪和氘灯光源连接,基于样品的紫外吸收特性,实现原位待测样品溶液浓度随时间变化的实时在线监测。编译光谱采集模块,进行样品溶液的光谱扫描,实现对物质的定性分析;编译标准曲线模块,实现对物质的定量分析方法的建立;编译样品检测模块,实现样品溶液浓度的实时连续测定。并以头孢氨苄为例,基于紫外吸收测定模式的LabVIEW软件编译的3个模块,同时对待测样品进行原位和过程分析,与紫外分光光度计测得结果比较(P>0.05),结果无显著性差异。说明LabVIEW软件编译的3个模块可实现待测溶液浓度的原位实时连续监测。
