离子阱时间串联质谱测定食品中的氯霉素

本文采用离子阱时间串联质谱法测定食品中氯霉素残留.样品经混合溶剂提取,C18小柱结合硅胶柱净化后,用双三甲基硅基三氟乙酰胺(BSTFA)衍生后,用GC/MS/MS测定.本法准确、稳定,检测灵敏度可达0.1 μg/kg.     

新型无卤阻燃剂双酚S-二(5,5-二甲基-1,3-二氧杂己内磷酸酯)的合成

以新戊二醇、三氯氧磷为原料,三乙胺为催化剂,合成了5,5-二甲基-1,3-二氧杂己内磷酰氯,再与双酚S反应得到高产率的新型无卤阻燃剂双酚S-二(5,5-二甲基-1,3-二氧杂己内磷酸酯),目标产物结构经IR,MS及1HNMR证实.热失重分析表明目标产物具有较高的热稳定性和良好的成炭性,起始分解温度为288.0℃,600℃时炭残余量达37.7%.     

某型航空发动机润滑油热衰变结构组成分析

利用高温反应釜与傅立叶红外光谱(FTIR)、气相色谱/质谱联用(GC/MS)技术,从分子水平分析添加有抗氧剂N-苯基-α-萘胺(T531)的聚α-烯烃(PAO)航空润滑基础油高温衰变,考察该润滑油的热安定性能.结果显示:低于200℃时,T531具有优良的抗氧化作用,能够较好地延缓基础油的高温衰变,但温度超过270℃后,T531的抗氧化性能降低,无法有效保护基础油.300℃高温产物经GC/MS分析,共检测到63种化合物,包括36种烷烃类化合物、25种烯烃类化合物、1种酮类化合物和抗氧剂T531,短链烷烃和烯烃的相对含量分别为5.835%和2.32%,是200℃高温时的20多倍,直接导致润滑油黏度的降低.在200℃高温反应油样中的T531相对含量仅为0.734%,远低于170℃和300℃反应后的2.019%和1.587%.可见,T531在200℃环境中消耗剧烈,对润滑基础油分子的抗氧化保护作用十分显著.     

光谱法研究Cu(Ⅱ)-核固红-盐酸吡硫醇体系及其分析应用

在弱酸性条件下,核固红,Cu(Ⅱ)与盐酸吡硫醇共存时,导致体系共振光散射强度明显增强.据此建立了测定盐酸吡硫醇的共振光散射分析法.在最佳条件下,Cu(Ⅱ)-核固红-盐酸吡硫醇体系的最大散射峰位于364nm处.共振光散射增强的程度与盐酸吡硫醇的浓度在0.5～11.5μg.mL-1之间呈良好的线性关系.方法的检出限为1.5×10-2μg.mL-1.将方法用于片剂中盐酸吡硫醇的测定,并与药典法进行对照,经t检验证明2种方法无显著性差异.     

水产品中碱性玫瑰精残留量的UPLC-MS/MS和LCMS-IT-TOF分析

建立了水产品中碱性玫瑰精测定的超高效液相色谱-串联质谱法(UPLC-MS/MS)和离子阱飞行时间质谱法(LCMS-IT-TOF)。样品经均质,以无水乙醇进行提取,通过Oasis HLB固相萃取小柱净化后进行UPLC-MS/MS和LCMS-ITTOF定性定量分析。结果表明,UPLC-MS/MS法在0.5~10.0μg/L范围内线性相关性好,相关系数为0.999 1,回收率在70%~120%之间,相对标准偏差低于15%,检测限为0.1μg/kg。自制阳性样品进行LCMS-IT-TOF定性,采用V飞行模式,根据正离子模式下获得的多级质谱数据,对比对照品碎裂特征,总结其多级裂解规律,进一步确证该非食用物质的添加使用。     

两种不对称四硫富瓦烯衍生物的合成、结构及电化学行为研究

以1,3-甲基二硫基-二硫醇-2-硫酮(化合物1)和1,3-环戊烯二硫基-二硫醇-2-硫酮(化合物5)为原料,在P(OEt)3存在下,分别与1,3-二(氰乙硫基)-二硫醇-2-氧酮(化合物3)发生不对称偶联,得到了两个新型的不对称四硫富瓦烯衍生物(化合物6a和6b).对二者进行了熔点、IR、1H NMR、13C NMR、MS、EA等表征,解析了其晶体结构,并对它们的电化学行为做了初步的研究.     

甜橙油微胶囊的制备及其热释放研究

以甜橙油(Sweet Orange Oil,SOO)为芯材,以明胶(GE)为囊材,以甲醛为固化交联剂,通过单凝聚法和真空干燥,成功制备了SOO/GE微胶囊.采用倒置显微镜、扫描电镜、傅里叶变换红外光谱、热重分析和热释放-气相色谱质谱法对SOO/GE微胶囊的形貌、包封率、热重分析和热释放行为进行了研究.结果表明,单凝聚法可有效包裹SOO,扫描电镜显示SOO/GE微胶囊具有完整和光滑的微球结构,包封率为88.5%,热重结果显示SOO/GE微胶囊的热释放温度在200～600℃区间,与SOO比较,SOO/GE微胶囊失重温度范围加大,释放时间增加.在100、200、300、400、500℃和600℃区间进行热分解,结果表明,甜橙微胶囊的热释放温度处于200～600℃之间,以明胶为壁材制备的微胶囊具有较好的微观结构和热释放能力.以上研究表明,甜橙油微胶囊在热加工食品、长效食品保鲜和烟草方面具有潜在的应用和开发前景.     

含硫的N-甲氧基氨基甲酸甲酯的合成及生物活性

为了寻找高效、低毒的新农药,采用活性结构拼接法合成了7个具有新型结构的N-甲氧基-N-[2-(甲硫基亚甲基-取代苯亚胺-硫亚甲基)苯基]氨基甲酸甲酯化合物.其结构经1H NMR,IR,LC/MS进行了表征.生物活性测定表明:5b,5g在50 mg/L下对稻瘟病(Pyricularia oryzae)的抑菌活性达90%.     

高效液相色谱-串联质谱法在全氟化合物检测中的应用

全氟有机化合物(Perfluorinated compounds,PFCs)是一类新型有机污染物,具有远距离迁移性、持久性、生物积累性和毒性,不仅对生态环境造成污染,且严重影响人类身体健康,因此PFCs的研究已逐渐成为国际上环境和健康领域的研究热点。当前,针对不同浓度水平的PFCs的检测方法主要有气相色谱-质谱法(GC-MS)、高效液相色谱-质谱法(HPLC-MS)和高效液相色谱-串联质谱法(HPLC-MS/MS)。其中HPLC-MS/MS因其高灵敏度和低检出限而被广泛应用于痕量PFCs的检测。本文概述了PFCs的应用、污染及研究现状,着重介绍了HPLC-MS/MS在PFCs检测方面的应用,并对HPLC-MS/MS在PFCs检测中的应用进行了展望。     

用液相色谱-串联质谱法测定蜂王浆中氯霉素残留量

提出了蜂王浆中氯霉素残留量测定的高效液相色谱-串联质谱联用(HPLC/MS/MS)法.采用C18 SPE萃取小柱净化蜂王浆样品,以电喷雾负离子多反应监测方式进行定性定量分析,并优化了提取、净化及仪器各项参数,测定结果重复性较好,氯霉素残留量在(0.1~0.3)×10-9之间,RSD小于10%时,方法的检出限为0.1×10-9,线性方程的相关系数为0.999 8,氯霉素残留量在(0.1~0.3)×10-9时回收率在90%~110%之间.所建立的方法可用于蜂王浆中低浓度氯霉素残留的分离检测.     

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