茶叶中多种农药残留的气相色谱法测定

采用氟罗里硅土／活性炭混合柱柱层析净化方法，以HP－5毛细管柱、电子捕获检测器（ECD）的气相色谱（GC）方法测定了茶叶中六六六、三氯杀螨醇、滴滴涕、联苯菊酯、甲氰菊酯、氯氰菊酯和氰戊菊酯等多种农药残留。所建立方法的分析结果与外检结果基本一致。方法具有溶剂使用量少、净化效果好、操作简便、快速等特点，可满足茶叶中多种农药残留检测的需要。     

茶叶中水胺硫磷、亚胺硫磷、甲基对硫磷和伏杀硫磷农药残留的高效液相色谱法测定

建立了茶叶中4种有机磷农药──水胺硫磷、亚胺硫磷、甲基对硫磷和伏杀硫磷残留的高效液相色谱测定方法.在45℃加温条件下用乙酸乙酯-正己烷(1◇1,by vol.)混合溶剂提取待测目标物、活性炭层析柱净化,用10.0 mL乙酸乙酯-正己烷(6◇1,by vol.)淋洗待测组分,以Eclipse XDB-C8色谱柱、乙腈-水混合液梯度洗脱分离、二极管阵列检测器测定.结果表明,上述4种农药在6.5 min内能很好地分离;样品中添加的待测组分能定量回收,回收率89.0%~108.0%,相对标准偏差为1.89%~5.96%(1.0μg/mL,n=5),检出限分别为:水胺硫磷9.82μg/kg、亚胺硫磷7.88μg/kg、甲基对硫磷2.19μg/kg、伏杀硫磷0.72μg/kg(dm).     

气相色谱法测定茶叶中菊酯类农药残留

近年来,茶叶的安全卫生已经在国际贸易中成为一种技术壁垒.如何用科学的方法,快速、准确地检测出茶叶中农药的残留量,对正确使用农药,提高茶叶质量,扩大出口起着重要作用.菊酯类农药是一类广谱性杀虫剂,具有高效、低毒、低残留等优点,近年来广泛用于茶园虫害的防治.本文介绍一种用气相色谱法测量茶叶中氯氰菊酯、氰戊菊酯、溴氰菊酯残留的方法.该方法采用微量化学法和固相萃取技术对样品进行提取及净化处理,在实际应用中效果较为理想.     

土壤中三种除虫菊酯类农药残留的气相色谱分析法及前处理条件浅探

本文探索了气相色谱法测定土壤中除虫菊酯类农药残留的方法,并探讨了提取剂、净化方式以及洗脱液等前处理过程对回收率的影响。土壤中残留的溴氰菊酯、氰戊菊酯与氯氰菊酯三种菊酯类农药,经2∶1(V/V)石油醚/丙酮提取,弗罗里硅土净化,用石油醚/乙酸乙酯进行洗脱,可以由气相色谱法一次进样同时分析测定,并能获得较好的回收率。方法快速、准确可靠,试剂用量小,能运用于实际工作。     

高效液相色谱测定蔬菜中拟除虫菊酯类农药残留

将自制的弗罗里硅土固相萃取柱用于蔬菜中拟除虫菊酯农药残留的研究,建立了固相萃取-高效液相色谱(SPE-HPLC)同时测定蔬菜中甲氰菊酯、三氟氯氰菊酯、溴氰菊酯、氰戊菊酯和氯菊酯农药残留的方法,测定了4种蔬菜样品,平均回收率分别为卷心菜80.7%~106.2%,花菜80.5%~102.6%,红萝卜63.0%~109.3%,青椒74.9%~109.0%,相对标准偏差≤14.5%.     

GC-NCI-MS分析粮谷中多类农药残留

 建立了粮谷中14种农药残留（9种有机氯、3种拟除虫菊酯和2种含氯有机氮）气相色谱-负化学源-质谱（GC-NCI-MS）的分析方法,试样样品用V(正己烷)∶V(丙酮)=1∶1超声波提取,硅镁吸附剂净化,采用GC-NCI-MS选择离子扫描方式检测.结果表明,该方法准确、快速、选择性好、抗干扰能力强,14种农药的方法最低检出限：0.01～0.18?μg/kg,平均添加回收率在75.2%～109.7%之间,变异系数都小于10%,并成功应用于大米、面粉试样中痕量农药残留分析.     

毛细管气相色谱法快速测定蔬菜中多农药残留

采用丙酮石油醚(丙酮∶石油醚=1∶1)为提取剂,对可能含有多种有机氯农药(氯氰菊酯、氰戊菊酯、溴氰菊酯、毒死蜱),以及可能含有多种有机磷农药(乐果、甲胺磷、对硫磷、氧化乐果)蔬菜样品进行同时提取并进行气相色谱分析.定性和定量分析结果表明,该方法样品预处理简单,分析速度快,结果准确可靠.     

凝胶渗透色谱-气相色谱串联质谱法测定禽蛋中16种有机氯类农药残留

建立了凝胶渗透色谱(GPC)净化、气相色谱-串联质谱(GC-MS/MS)同时测定禽蛋中16种有机氯类农药残留的方法.样品中的待测农药组分经丙酮、正己烷提取、GPC净化去除油脂等杂质,GC-MS/MS采用多反应监测模式(MRM)采集数据后进行定性/定量分析.待测农药的标准加入回收率在70％～110％之间,方法的相对标准偏...     

高效液相色谱检测番茄与土壤中的吩胺霉素残留

吩胺霉素是我国具有自主知识产权的新型抗生素类杀菌剂.选取番茄及三类理化性质不同的土壤为研究对象,建立了吩胺霉素在上述基质中的液相色谱检测方法.土壤中吩胺霉素选择混合液(V_(氨水)∶V_(乙醇)∶V_(二氯甲烷)=1∶2∶3)振荡提取,番茄中吩胺霉素采用乙腈振荡提取,碱性氧化铝柱净化.土壤与番茄中的平均回收率分别为80.2%~95.7%和80.1%~85.6%,RSD(相对标准偏差)分别为2.14%~4.17%和4.12%~5.17%.吩胺霉素的最小检出量为0.2ng,在基质中最低检测限为0.01mg/kg.本方法简单可靠,基质效应弱,符合农药残留分析要求,可用于土壤和番茄中吩胺霉素的残留检测.     

毛细管气相色谱法测定无公害柿子中菊酯类农药的残留量

建立的一种测定无公害水果柿子中2种拟除虫菊酯农药残留量的毛细管气相色谱法,是样品经丙酮提取、石油醚萃取、柱色谱净化,采用短毛细管柱(OV-101,15 m)进行分析和电子捕获检测器(ECD)检测及外标法定量,结果缩短了色谱分析时间,加标回收率w(氰戊菊酯)为96.81%,w(溴氰菊酯)为81.23%。     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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     

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