TurboFlow在线净化是一种结合涡流扩散、体积排阻及化学作用原理的在线样品纯化技术,具有自动化程度高、操作步骤少、实验误差小以及试剂使用量小等优点,与液相色谱-串联质谱(Liquid Chromatography-Tandem Mass Spectrometry,LC-MS/MS...TurboFlow在线净化是一种结合涡流扩散、体积排阻及化学作用原理的在线样品纯化技术,具有自动化程度高、操作步骤少、实验误差小以及试剂使用量小等优点,与液相色谱-串联质谱(Liquid Chromatography-Tandem Mass Spectrometry,LC-MS/MS)联合使用,不仅能简化样品前处理步骤,还能实现对目标化合物的高灵敏度、高准确度和高通量的检测,被广泛应用于食品安全检验领域。本文介绍TurboFlow在线净化-液相色谱-串联质谱(TurboFlow Online Cleanup-Liquid Chromatography-Tandem Mass Spectrometry,TF-LC-MS/MS)技术的原理和优势,讨论该技术在食品安全检测中的应用,旨在进一步提高食品安全检验能力,助力食品安全监管。展开更多
目的基于HPLC研究柏子仁中4种黄曲霉毒素的污染情况,并进行风险分析,评估柏子仁的用药安全。方法采用Agilent Eclipse Plus C 18(4.6×250 mm 5μm)为色谱柱,柱后光化学衍生法检测,以甲醇∶乙腈∶水(35∶10∶55)为流动相,流速1.0 mL...目的基于HPLC研究柏子仁中4种黄曲霉毒素的污染情况,并进行风险分析,评估柏子仁的用药安全。方法采用Agilent Eclipse Plus C 18(4.6×250 mm 5μm)为色谱柱,柱后光化学衍生法检测,以甲醇∶乙腈∶水(35∶10∶55)为流动相,流速1.0 mL·min^(-1);柱温:40℃;荧光检测器检测。结果黄曲霉毒素B 1、B 2、G 1、G 2分别在0.35~20.8μg·L^(-1)、0.13~7.6μg·L^(-1)、0.36~21.6μg·L^(-1)、0.13~7.6μg·L^(-1)范围内呈良好的线性关系,黄曲霉毒素B 1、B 2、G 1、G 2平均回收率分别为90.6%、83.46%、87.84%、86.58%,相对偏差分别为2.9%、3.6%、3.6%、4.7%。23批柏子仁中有14批检出黄曲霉毒素B 1和总量,残留量分别在1~4μg·kg^(-1)和1~5μg·kg^(-1)之间,均符合规定,但检出率高达61%,存在安全隐患。结论该方法简单、准确、方便,能有效评价柏子仁中黄曲霉毒素的污染情况。警示柏子仁易受黄曲霉毒素的污染,需加强柏子仁监管力度和不定期的专项抽检,降低安全风险,以确保临床用药安全。展开更多
The rotary water jetting is one of the most important techniques for horizontal well cleanup.The jet flow is used to remove plugging particles from sand control screens to recover their permeability.Currently,the oper...The rotary water jetting is one of the most important techniques for horizontal well cleanup.The jet flow is used to remove plugging particles from sand control screens to recover their permeability.Currently,the operation optimization of this technique depends mainly on experience due to absence of applicable evaluation and design models for removing plugging materials.This paper presents an experimental setup to simulate the cleanup process of plugged screens by rotary water jetting on the surface and to evaluate the performance of a jetting tool.Using real plugged screens pulled from damaged wells,a series of tests were performed,and the qualitative relationships between the cleanup efficiency and various operational parameters,such as the type of fluids used,flow rate,mode of tool movement,etc.,were obtained.The test results indicated that the cleanup performance was much better when the rotary jetting tool moved and stopped periodically for a certain time than that when it reciprocated at a constant speed.To be exact,it was desirable for the rotary jetting tool to move for 1.5-2 m and stop for 2-4 min,which was called the ＂move-stop-move＂ mode.Good cleanup performance could be obtained at high flow rates,and the flow rate was recommended to be no lower than 550-600 L/min.The test results also indicated that complex mud acid was better than clean water in terms of cleanup performance.Good cleanup efficiency and high screen permeability recovery could be achieved for severely plugged screens.Rotary jetting is preferred for the cleanup of horizontal wells with severely plugged screens,and the screen permeability recovery ratio may reach 20％ if optimized operation parameters were used.展开更多
The objectives of this study were to optimize instrumental parameters and conditions for analysis of selected organop- hosphorus pesticides (OPPs) by gas chromatography (GC) with nitrogen-phosphorus detection (NPD) (G...The objectives of this study were to optimize instrumental parameters and conditions for analysis of selected organop- hosphorus pesticides (OPPs) by gas chromatography (GC) with nitrogen-phosphorus detection (NPD) (GC-NPD); to select an appropriate solvent system; to conduct a comparison of sonication and shaking extractions; and to select an appropriate procedure for extracting organophosphorus pesticides from soils. Procedure I consisted of n-hexane or petroleum ether together with acetone used as solvents, while Procedure contained several solvents including acetone, methanol, dichloromethane, and n-hexane or petroleum ether. Experimental results indicated that a mixture of petroleum ether/acetone (2:1, v/v) could be used in place of n-hexane/acetone (2:1, v/v) as it was a less expensive solvent system. In addition, shaking under a water bath at 20 °C was more effective than sonication. Also, Procedure I was more effective, safer, and more timesaving than Procedure Procedure I was applied to three soil types of different organic matter content, with recoveries of the OPPs from the yellow-brown soils, which had a higher organic matter content, being lower than those from the yellow and red soils.展开更多
In this paper, a polyethersulfone （PES）/multi-walled carbon nanotubes （MWCNTs） composite membrane was prepared us- ing phase inversion. The surface morphology and internal structure of the membrane were observed b...In this paper, a polyethersulfone （PES）/multi-walled carbon nanotubes （MWCNTs） composite membrane was prepared us- ing phase inversion. The surface morphology and internal structure of the membrane were observed by scanning electron microscopy （SEM）. The effects of MWCNTs content on various aspects of membrane performance such as porosity, water flux, and antifouling characteristics were investigated. Results showed that proper addition of MWCNTs would improve the properties of the membrane. MWCNTs had a strong adsorption capacity for industrial dyes and the composite membrane could be used as an effective method to identify and clean up illegal dyes in foods. In addition, this new method for iden- tifying dyes is rapid： the cleanup procedure in the determination of illegal dyes in foods by the composite membrane was shortened to 30 min or less compared to 6-8 h for traditional methods.展开更多
A simple process of purifying and activating sepiolite is introduced. Impure minerals in sepiolite can be removed by fully agitating the sepiolite suspension to which a few amount of disperser has been added. After be...A simple process of purifying and activating sepiolite is introduced. Impure minerals in sepiolite can be removed by fully agitating the sepiolite suspension to which a few amount of disperser has been added. After being purified and activated, fine sepiolite particles present prior properties such as increased specific area,better dispersiveness and increased adsorptivity, moreover, the pulping ratio can be raised from original 4-5m3/2 to 20m3 /t. The process with simple technique and utilizing cheap chemical agents extends the application of low-grade sepiolite.展开更多
The experimental work has been carried out to study the absorption-desorption properties of the silica aerogels, for their use in oil spill cleanup application. For these studies, silica aerogel granules were prepared...The experimental work has been carried out to study the absorption-desorption properties of the silica aerogels, for their use in oil spill cleanup application. For these studies, silica aerogel granules were prepared by two step acid– base catalyzed sol–gel process, involving ambient pressure drying of alcogels, were made use for absorption & desorption studies of different organic liquids. The optimal molar ratio of precursors tetraethoxysilane (TEOS):Methanol (MeOH):Oxalic acid:NH4OH:NH4F:trimethylchlorosilane (TMCS) was kept constant at 1:16.5:0.71:0.58:0.60:0.98, respectively. In all, four alkanes, four aromatic compounds, four alcohols and three oils were used for absorption and desorption studies of organic liquids. The absorption capacity of aerogel sample was quantified by measuring the mass of the organic liquid absorbed by unit mass of the aerogel sample. The hydrophobic aerogel granules showed a very high uptake capacity and high rate of uptake. The desorption of solvents and oils was studied by keeping the liquid absorbed aerogel granules at various temperatures and weighing them at regular time intervals until all the absorbed liquid got totally desorbed. The Fourier transform infrared spectroscopy analysis showed that the aerogel structure was not much affected by the solvent absorption, while the oil absorption led to the shrinkage, resulting in a dense structure after desorption.展开更多
文摘TurboFlow在线净化是一种结合涡流扩散、体积排阻及化学作用原理的在线样品纯化技术,具有自动化程度高、操作步骤少、实验误差小以及试剂使用量小等优点,与液相色谱-串联质谱(Liquid Chromatography-Tandem Mass Spectrometry,LC-MS/MS)联合使用,不仅能简化样品前处理步骤,还能实现对目标化合物的高灵敏度、高准确度和高通量的检测,被广泛应用于食品安全检验领域。本文介绍TurboFlow在线净化-液相色谱-串联质谱(TurboFlow Online Cleanup-Liquid Chromatography-Tandem Mass Spectrometry,TF-LC-MS/MS)技术的原理和优势,讨论该技术在食品安全检测中的应用,旨在进一步提高食品安全检验能力,助力食品安全监管。
文摘The rotary water jetting is one of the most important techniques for horizontal well cleanup.The jet flow is used to remove plugging particles from sand control screens to recover their permeability.Currently,the operation optimization of this technique depends mainly on experience due to absence of applicable evaluation and design models for removing plugging materials.This paper presents an experimental setup to simulate the cleanup process of plugged screens by rotary water jetting on the surface and to evaluate the performance of a jetting tool.Using real plugged screens pulled from damaged wells,a series of tests were performed,and the qualitative relationships between the cleanup efficiency and various operational parameters,such as the type of fluids used,flow rate,mode of tool movement,etc.,were obtained.The test results indicated that the cleanup performance was much better when the rotary jetting tool moved and stopped periodically for a certain time than that when it reciprocated at a constant speed.To be exact,it was desirable for the rotary jetting tool to move for 1.5-2 m and stop for 2-4 min,which was called the ＂move-stop-move＂ mode.Good cleanup performance could be obtained at high flow rates,and the flow rate was recommended to be no lower than 550-600 L/min.The test results also indicated that complex mud acid was better than clean water in terms of cleanup performance.Good cleanup efficiency and high screen permeability recovery could be achieved for severely plugged screens.Rotary jetting is preferred for the cleanup of horizontal wells with severely plugged screens,and the screen permeability recovery ratio may reach 20％ if optimized operation parameters were used.
基金1Project supported by the Outstanding Youth Fund of the National Natural Science Foundation of China (No. 40325001),the National Key Basic Research Support Foundation of China (Nos. 2002CB415203 and 2002CB410805) and the Knowl-edge Innovation Program of
文摘The objectives of this study were to optimize instrumental parameters and conditions for analysis of selected organop- hosphorus pesticides (OPPs) by gas chromatography (GC) with nitrogen-phosphorus detection (NPD) (GC-NPD); to select an appropriate solvent system; to conduct a comparison of sonication and shaking extractions; and to select an appropriate procedure for extracting organophosphorus pesticides from soils. Procedure I consisted of n-hexane or petroleum ether together with acetone used as solvents, while Procedure contained several solvents including acetone, methanol, dichloromethane, and n-hexane or petroleum ether. Experimental results indicated that a mixture of petroleum ether/acetone (2:1, v/v) could be used in place of n-hexane/acetone (2:1, v/v) as it was a less expensive solvent system. In addition, shaking under a water bath at 20 °C was more effective than sonication. Also, Procedure I was more effective, safer, and more timesaving than Procedure Procedure I was applied to three soil types of different organic matter content, with recoveries of the OPPs from the yellow-brown soils, which had a higher organic matter content, being lower than those from the yellow and red soils.
基金supported by the Fund of Key Projects of Higher Education in Henan Province, China (17A550018)the Fund of Henan Province Science and Technology Research Project, China (172102310314)
文摘In this paper, a polyethersulfone （PES）/multi-walled carbon nanotubes （MWCNTs） composite membrane was prepared us- ing phase inversion. The surface morphology and internal structure of the membrane were observed by scanning electron microscopy （SEM）. The effects of MWCNTs content on various aspects of membrane performance such as porosity, water flux, and antifouling characteristics were investigated. Results showed that proper addition of MWCNTs would improve the properties of the membrane. MWCNTs had a strong adsorption capacity for industrial dyes and the composite membrane could be used as an effective method to identify and clean up illegal dyes in foods. In addition, this new method for iden- tifying dyes is rapid： the cleanup procedure in the determination of illegal dyes in foods by the composite membrane was shortened to 30 min or less compared to 6-8 h for traditional methods.
文摘A simple process of purifying and activating sepiolite is introduced. Impure minerals in sepiolite can be removed by fully agitating the sepiolite suspension to which a few amount of disperser has been added. After being purified and activated, fine sepiolite particles present prior properties such as increased specific area,better dispersiveness and increased adsorptivity, moreover, the pulping ratio can be raised from original 4-5m3/2 to 20m3 /t. The process with simple technique and utilizing cheap chemical agents extends the application of low-grade sepiolite.
文摘The experimental work has been carried out to study the absorption-desorption properties of the silica aerogels, for their use in oil spill cleanup application. For these studies, silica aerogel granules were prepared by two step acid– base catalyzed sol–gel process, involving ambient pressure drying of alcogels, were made use for absorption & desorption studies of different organic liquids. The optimal molar ratio of precursors tetraethoxysilane (TEOS):Methanol (MeOH):Oxalic acid:NH4OH:NH4F:trimethylchlorosilane (TMCS) was kept constant at 1:16.5:0.71:0.58:0.60:0.98, respectively. In all, four alkanes, four aromatic compounds, four alcohols and three oils were used for absorption and desorption studies of organic liquids. The absorption capacity of aerogel sample was quantified by measuring the mass of the organic liquid absorbed by unit mass of the aerogel sample. The hydrophobic aerogel granules showed a very high uptake capacity and high rate of uptake. The desorption of solvents and oils was studied by keeping the liquid absorbed aerogel granules at various temperatures and weighing them at regular time intervals until all the absorbed liquid got totally desorbed. The Fourier transform infrared spectroscopy analysis showed that the aerogel structure was not much affected by the solvent absorption, while the oil absorption led to the shrinkage, resulting in a dense structure after desorption.
