ASE-GC法测定土壤中18种有机磷农药

］研究了利用加速溶剂萃取—双塔双柱气相色谱法（ASE-GC）分析土壤中的18种有机磷农药（OPPs）.结果表明:加速溶剂萃取对18种目标化合物萃取回收率达到82%～98%,单个样品萃取时间约15 min,方法快速;双塔双柱气相色谱法测定土壤中18种目标化合物样品测试时间约40 min,18种化合物检出限在0.282~1.05 μg/kg之间,各化合物校准曲线的相关系数在0.9979~0.9999之间,双柱确认的相对偏差在-2.0%~2.0%之间     

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%。     

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).     

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.     

气相色谱法测定农产品中8种有机氯农药的残留

建立了气相色谱测定食品中六六六4种同分异构体和滴滴涕4种同分异构体残留量的方法.样品由丙酮/石油醚提取,微型化磺化反应进行净化,采用气相色谱仪测定,外标法定量.结果表明:在5~100 g/L范围内8种有机氯农药的线性良好;所有农药的LOD范围为0.59~5.37 g/kg,LOQ为1.97~17.86 g/kg;在5、10、20 g/kg 3个添加水平下,8种农药的平均回收率在74.0%~106.1%之间,且RSD均小于11%.该方法简单、快速,准确度和精密度高,抗干扰能力强,可用于茶叶、姜、柑橘等农产品中8种有机氯农药的检测.     

金银花中有机磷农药残留分析及其冲泡过程迁移模型研究

为确保消费者饮茶安全,建立了QuEChERS-GC-MS/MS快速测定金银花和其茶汤中6种有机磷农药(对硫磷、倍硫磷、特丁硫磷、治螟磷、丙溴磷、灭线磷)残留的检测方法。金银花和茶汤分别经乙腈和乙酸乙酯提取、盐析离心、混合净化剂(10mg MWCNTs、15mg PSA、150mg无水硫酸镁)净化、0.22μm滤膜过滤后,供GC-MS/MS检测。结果表明:金银花和茶汤中,有机磷农药在1~1000μg/kg和1~1000μg/L呈现良好的线性关系,R²>0.991;在4个添加水平下,回收率在67.2%～110.3%,相对标准偏差小于19%(n=6);金银花和茶汤中,有机磷农药定量限分别为1μg/kg和1μg/L。在此基础上,深入研究了金银花在冲泡过程中6种有机磷农药的迁移预测模型,表明农药迁移率(TR) 与农药的正辛醇-水分配系数(Kow)关联性较大,由此获得预测模型为lg TR=-0.5362lg Kow+3.9152(lg Kow＞3),R²= 0.914,拟合度较好;而农药迁移率与水溶解度(Ws)并未表示出关联性。该检测方法和迁移模型的建立将有利于更深层次认知农药化学污染物在金银花浸泡过程中的迁移行为,以期为制定金银花中有机磷农药最大残留限量标准提供科学依据和技术支撑。     

基于ABS塑料管为保护装置的S-LPME-HPLC测定水体中有机磷农药

用多孔的ABS塑料管水平放置的方式保护静态液相微萃取的一滴溶剂,并由此建立了静态液相微萃取与高效液相色谱联用测定水体中甲基对硫磷和对硫磷的分析方法.考察了萃取溶剂、萃取溶剂体积、萃取时间以及搅拌速度对液相微萃取的影响,并对HPLC操作条件进行了优化.该方法对2种有机磷农药的线性范围均为0.05~1.00μg·L-1,相关系数R为0.999 3~0.999 5,回收率为95.2%~102%,相对标准偏差(n=7)3.5%~6.8%,检出限(3S/N)0.01μg·L-1.结果表明:用该方法测定水体中有机磷农药残留是可行的.     

微型流动注射化学发光仪测定蔬菜中残留的有机磷农药

目的利用便携式流动注射化学发光仪和紫外降解装置,检测蔬菜中残留的有机磷农药。方法过硫酸钾在紫外光的催化下能将有机磷降解为无机磷,无机磷在酸性条件下可以和钒酸盐、钼酸盐反应生成具有氧化性的磷钼钒杂多酸,可直接氧化鲁米诺产生强而稳定的化学发光信号;根据发光强度与磷的浓度在一定范围内呈线性关系,从而实现有机磷农药的定量测定。结果测定磷的检出限为1.0×10-10g/mL,线性范围为1.0×10-9~3.0×10-6g/mL,对浓度为2.0×10-7g/mL的磷平行测定11次,相对标准偏差为2.1%;当青菜中有机磷农药的添加浓度为1.00 mg/kg和2.00 mg/kg时,方法回收率在89.5%~113.5%之间。结论此方法简便快捷、准确可靠,实现了检测仪器的自动化和微型化,为市售蔬菜中有机磷农药残留的现场检测奠定了基础。     

六种中药材中的有机氯农药残留量的测定

用气相色谱法同时测定了中药材天仙子、半夏、杜仲、吴茱萸、何首乌、茯苓中的有机氯农药的残留量.结果表明,13种有机氯农药在1~100μg/L范围内线性关系良好(r>0.995 5),检出限为0.04~0.22μg/L,添加回收率均在80%~102%.该方法符合农药残留检测标准.     

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。     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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