气相色谱-串联质谱检测烟草中10种酰胺类除草剂残留

采用固相萃取-气相色谱-串联质谱来测定烟草中10种酰胺类除草剂的残留量。烟草样品通过含1%乙酸的乙腈混合液提取,固相萃取净化,采用气相色谱分离,串联质谱多反应监测模式分析。10种酰胺类除草剂在0.01~1.0 mg/L线性范围内均呈良好线性关系,相关系数大于0.997,方法的检出限在0.2~4.7μg/kg之间。在10μg/kg,50μg/kg,100μg/kg等3个浓度水平下进行加标实验,其加标回收率在79.6%~101.4%之间,测定值的相对标准偏差(n=6)在1.6%~6.7%之间。建立的方法简便、快速、灵敏,为常见烟草中酰胺类除草剂残留的准确判断提供了可靠依据,适用于烟草中10种酰胺类除草剂的同时检测。     

QuEChERS结合UPLC-MS/MS测定菠菜中5种氨基甲酸酯类农药残留

建立了基于QuEChERS技术的超高效液相色谱-串联质谱法(UPLC-MS/MS),对菠菜中的5种氨基甲酸酯类农药残留量进行测定。样品均质后,以乙腈-水(体积比50∶50)提取后,盐析离心,乙腈层用N-丙基乙二胺净化后供UPLC-MS/MS测定。采用电喷雾离子源ESI正离子模式电离,质谱多反应监测模式对目标母离子和子离子进行扫描测定。5种氨基甲酸酯类农药在0.1~20.0μg/L的基质曲线范围内呈良好线性关系,相关系数r大于0.9991,3个水平的平均加标回收率为91.0%~101.0%,方法检出限和定量限分别为0.10~0.20μg/kg和0.25~0.50μg/kg,相对标准偏差为2.15%~5.57%。该方法具有操作简便、快速高效、回收率高、灵敏度高、重复性好等优点,可用于测定菠菜中的5种氨基甲酸酯类农药残留量。     

蜂蜜中多种有机磷农药残留的液相色谱串联质谱检测

针对敌百虫、敌敌畏和蝇毒磷为常用的防治蜜蜂天敌或虫害的有机磷农药杀虫剂,易在蜂蜜中产生残留,建立了蜂蜜中敌百虫、敌敌畏和蝇毒磷残留的液相色谱串联质谱(LC-MS/MS)同时测定方法。蜂蜜样品经乙酸乙酯提取、浓缩,用甲醇溶解残渣,液相色谱(LC)分离,电喷雾(ESI)-MS/MS多反应监测(MRM)模式检测,外标基体曲线定量。3种有机磷农药在20～500μg/L范围内线性响应良好,相关系数均大于0.994;获得的检出限均为0.1μg/kg,定量限均为4μg/kg。在加标浓度为10～40μg/kg范围内,平均回收率为78.5%～96.8%,相对标准偏差为9.1%～13.1%。     

LC-MS/MS 法测定大棚蔬菜氨基甲酸酯 类农药残留分析研究

利用LC-MS/MS分析系统,建立了蔬菜中氨基甲酸酯类农药残留分析方法,并测定了6种叶子菜中的农药残留量.结果表明,氨基甲酸酯类农药甲萘威、抗蚜威、克百威在0.05~100 ng/m L范围内线性回归良好,相关系数R2均大于0.9990,检出限在0.02~0.09μg/kg之间,定量限在0.07~0.28μg/kg之间,平均加标回收率均大于81.3%,相对标准偏差均低于9.82%.本法灵敏度高、准确性好、精密度好、选择性强、分析速度快,应用范围广,可以满足对蔬菜中氨基甲酸酯类农药残留的分析检测要求.     

磁性石墨烯-液质联用测定鸡肉中万古霉素和喹诺酮

建立了鸡肉中万古霉素和喹诺酮类药物残留的磁性石墨烯固相萃取-液相色谱-串联质谱分析方法.样品采用乙腈提取,磁性石墨烯粉分散固相萃取净化,经Agilent ZORBAX SB-C18(3.0 mm ×100.0 mm,1.8 μm)色谱柱分离,液相色谱-串联质谱仪进行检测.目标物在2.0~50.0 μg/L内线性关系良好(r²>0.99).鸡肉基质中目标化合物在5、10、25 μg/kg加标水平的回收率为71.2%~98.8%,相对标准偏差(RSD)为6.8%~14.3%.该方法净化效果好,回收率高,精密度好,可用于鸡肉中万古霉素和喹诺酮类药物残留检测.     

食品中常见有机磷农药残留的气相色谱-质谱检测方法

建立了气相色谱-质谱联用技术分析蔬菜、谷物中敌敌畏、甲胺磷等16种有机磷农药残留的快速检测方法。样品用乙腈提取,采用Qu ECh ERS处理方法进行前处理,用气相色谱-质谱联用多反应监测仪检测16种有机磷农药残留。16种有机磷农药在15 min内流出,分离度良好,农药在0.025~0.4 mg/kg范围内线性良好,相关系数(R2)均大于0.94。不同基质如大米、面粉、蔬菜的加标回收率分别为75.9%~112.2%、77.3%~126.9%、76.2%~125.3%,相对标准偏差(RSD)8.5%。重复性实验引入的不确定度符合国家标准。该方法具有操作方便、分离时间短、灵敏度高、选择性好等优点,适用于大多数食品中有机磷农药残留检测。     

调味品中罗丹明B的高效液相色谱-串联质谱法测定及不确定度评价

建立高效液相色谱-串联质谱测定调味品中非法添加罗丹明B的分析方法,评定测定结果的不确定度。样品用乙腈提取后,经MCX固相萃取柱净化,Acclaim C18色谱柱分离,以甲醇和0.05%甲酸水溶液为流动相;串联质谱,电喷雾正离子(ESI+)模式电离,多反应监测(MRM)模式分析测定。结果表明:罗丹明B在1.0~40.0μg/kg范围内呈现良好的线性关系,相关系数R2=0.999 6,检出限为0.2μg/kg,加标回收率为67.40%~125.20%,相对标准偏差(RSD)≤4.950%。另外,从标准品溶液配制、标准曲线拟合、样品称量、仪器、样品溶液测定重复性等方面,评定了测定结果的不确定度。该方法具有操作简单、灵敏度高、分析时间短、结果准确等优点,适合于大批样品中罗丹明B含量的测定。     

蔬菜中12种有机氯农药残留的QuEChERS/GC-QqQ-MS/MS测定

建立QuEChERS前处理结合气相色谱-三重四级杆串联质谱(GC-QqQ-MS/MS)法用于测定蔬菜中六六六、狄氏剂、艾氏剂、七氯、五氯硝基苯、氯丹、硫丹等12种有机氯农药残留同时检测的分析方法.样品经乙腈提取,QuEChERS方法净化后,经GC-QqQ-MS/MS在多反应离子监测(MRM)模式下分析测定,外标法定量. 12种有机氯农药在5~100 ng/m L范围内线性关系良好,线性相关系数(R2)超过0. 999 1;在黄瓜样品基质中添加10、40和100 ng/m L 3个浓度水平下,平均加标回收率为68. 80%~97. 18%; RSD(n=6)为0. 95%~11. 07%. 12种有机氯农药的检出限均小于1. 5μg/kg.该法灵敏度高,适用于蔬菜中有机氯农残的检测工作.     

高效液相色谱-串联质谱(HPLC-MS/MS)法测定茶叶中高关注的25种农药残留

本文建立了茶叶中25种常用农药多残留同时检测的液相色谱-串联质谱(HPLC-MS/MS)检测方法。样品以乙腈作为提取剂,经石墨化炭固相萃取小柱净化,采用phenomenex C18色谱柱(50 mm×2.1 mm,2.6μm,100 A)分离,以乙腈-0.1%甲酸水溶液为流动相梯度洗脱,以电喷雾电离(ESI)、多反应监测(MRM)模式检测,外标法定量。25种农药在5-200μg/L范围内,线性相关系数均大于0.99,线性良好。分析目标物添加水平为0.01-0.10 mg/kg时,回收率范围为70%-116%,RSD范围为4.3%-10.8%,符合残留分析的要求。25种农药的定量下限(S/N10)为0.01 mg/kg。该方法的提取效果好、净化较彻底,灵敏度满足国内外限量标准的要求,适合茶叶中常用农药残留的同时测定。     

液-质联用测定鱼体内甲基磺草酮的残留量

为了检测鱼体内甲基磺草酮的残留量,建立液相色谱串联质谱的方法测定甲基磺草酮。结果表明:在0.5~100μg/L浓度范围内,线性相关系数(r)为0.998 6。当添加质量分数为0.1~10μg/g时,甲基磺草酮在鱼体内的平均回收率为80.0%~99.3%,RSD为3.4%~8.4%。该方法的最小检出量为5.0×10-12g,鱼体内的最低检测质量分数(LOQ)为0.1μg/g。该方法操作简单可靠,准确度、精密度及其灵敏度均满足农药残留分析的要求,可用于鱼体内甲基磺草酮残留量的测定。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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