柱前荧光标记结合高效液相色谱-质谱联用技术分析花粉中饱和及不饱和脂肪酸

以荧光试剂苯并[b]吖啶酮-5-乙基对甲苯磺酸酯(BAETS)作为柱前衍生化试剂,对27种饱和脂肪酸和7种不饱和脂肪酸进行了优化衍生.在Hypersil BDS C8色谱柱(4.6 ×200 mm i.d,5 μm)上,采用梯度洗脱对34种混合脂肪酸(FFA)衍生物进行了分离及定性定量分析.荧光检测激发和发射波长分别为λex=273 nm,λem=503 nm.多数脂肪酸的线性回归系数大于0.9995,检测限在11.70-68.25 fmol.采用大气压化学电离源(APCI)的正离子模式,实现了花粉中FFA组分的质谱鉴定.建立的方法具有良好的重现性,对实际样品测定结果满意.     

柱前衍生-高效液相色谱荧光检测法测定高寒沼泽牧草及藻体中脂肪酸含量

为了研究牧草及藻体内脂肪酸组成的差异,本研究以N-乙基-N,-[(3-二甲氨基)丙基]碳二亚胺盐(EDC)的乙腈溶液为催化剂,采用新型荧光试剂10-甲基吖啶酮-2-磺酰哌嗪(MASP)作为柱前衍生试剂,对19种混合脂肪酸进行优化衍生,以λex=315 nm和λem=430 nm分别为荧光检测的激发和发射波长,采用梯度洗...     

反相高效液相色谱荧光衍生法测定土壤中的脂肪酸及质谱定性

利用新型荧光试剂1,2-苯并-3,4-二氢咔唑-9-乙醇（BCE）作为柱前衍生化试剂,在Eclipse XDBC8色谱柱上,通过梯度洗脱对19种游离脂肪酸进行了分离和在线质谱定性．以乙腈为溶剂,1-乙基-3-（3-二甲氨基丙基）环己碳二亚胺（EDAC）作为缩合剂,4-二甲氨基吡啶为碱催化剂（DMAP）,60℃下衍生反应40min后获得稳定的荧光产物．激发和发射波长分别为λex-333nm,λem-390nm．采用大气压化学电离源（APCI）正离子模式．实现了土壤中脂肪酸的定性及相应含量测定．脂肪酸的线性回归系数大于0．9993,检测限在11．79-33．04fmol．     

荧光检测结合高效液相色谱-质谱技术同时测定大鼠脑组织中7种神经递质

采用新型荧光试剂2-[2-(7H-二苯并[a,g]咔唑-乙氧基)]-乙基氯甲酸酯(DBCEC-Cl)作为柱前衍生试剂在Hypersil BDS C18(4.6mm×200mm×5(m)反相色谱柱上,利用程序洗脱对7种神经递质衍生物进行了分离检测,在乙腈和硼砂缓冲液中,40℃恒温水浴反应5 min即可实现完全衍生.荧光激发和发射波长:(ex=300nm、(em=395nm.采用柱后质谱电喷雾离子源(ESI source)正离子模式,实现了小鼠脑组织中神经递质的定性定量检测.线性回归相关系数大于0.9870,检出限为1.21-4.28fmol(S/N=3).     

柱前衍生化HPLC荧光法测定脂肪胺化合物

采用新型荧光试剂4-（1-甲基-1H-菲并[9,10-d]咪唑-2-）苯甲酸（MPIBA）进行柱前衍生并经荧光检测对脂肪胺进行了高效液相色谱（HPLC）分离.衍生物的荧光激发和发射波长分别为λex=260 nm,λem=446 nm.80℃下在四氢呋喃（THF）溶剂中用N-乙基-N-′[（3-二甲氨基）丙基]碳二亚胺盐酸盐（EDC）作催化剂,衍生反应10min后获得稳定的荧光产物.在Eclipse XDB-C8色谱柱（4.6×150 mm,5 mm）上,采用梯度洗脱对12种游离脂肪胺衍生物进行了优化分离,实现了各种脂肪胺衍生物的快速、准确测定.该方法具有良好的重现性,多数脂肪胺的线性回归系数大于0.9996,检测限在10.5-53.4 fmol范围内,对实际样品臭豆腐中脂肪胺的测定测定结果满意.     

荧光标记—高效液相色谱法测定栝楼中游离脂肪酸

合成制备了一种荧光标记试剂(2-(9吖啶酮)-乙酰肼),并成功应用于高压液相色谱法测定脂肪酸。2-(9吖啶酮)-乙酰肼与脂肪酸的衍生反应可在20分钟内完成。衍生物具有良好的荧光性质,激发和发射波长分别为260 nm和430nm。采用梯度洗脱使得20种脂肪酸在BDS–C8反相柱上得到良好分离,20种脂肪酸的线性系数均>0.996。当采用20mg栝楼样品进行分析时,脂肪酸检出限(三倍信噪比)在0.21–1.20μg/g之间。采用这种荧光试剂衍生的方法对栝楼根、茎、叶和果皮中的游离脂肪酸的含量进行定量分析。     

荧光试剂衍生化液相色谱分析生物检材中的氟乙酸钠

建立了使用新的荧光衍生试剂9-氯甲基蒽(CA)衍生化生物检材中的氟乙酸钠,并通过薄层色谱和荧光检测的高效液相色谱(HPLC)分析的方法。合成得到氟乙酸钠的荧光衍生物——氟乙酸-9-亚甲基蒽酯(MA-MFA),纯度达到98%以上,通过红外光谱、核磁共振、元素分析和质谱对其进行结构表征。薄层色谱中展开剂为石油醚/乙酸乙酯(体积比为95∶5),检测限为5×10-8g(TLC)。高效液相色谱用AgilentHypersilODS反相色谱柱,以乙腈/水(体积比为85∶15)为流动相,荧光检测波长λex为256 nm,λem为412 nm。方法在2.5×10-9~125×10-9mol/mL浓度范围内呈良好的线性关系,线性相关系数为0.9988,生物样品空白添加实验的回收率为83%~90%,最低检测限为2×10-10g(S/N=3),日内、日间RSD均小于4%。该方法用于中毒死亡者的血液样品及其他检材的测定,效果良好。     

新型荧光试剂用于儿茶酚胺类神经递质的高效液相色谱检测

利用新型荧光试剂1,3,5,7-四甲基-8-苯基-(4'-O-(N-琥珀酰亚胺乙酸酯))-二氟化硼-二吡咯甲烷(TMPAB-OSu)为柱前衍生化试剂,在氰基色谱柱上通过梯度洗脱对三种儿茶酚胺神经递质进行了分离和检测.以乙腈-水为溶剂,pH7.5的硼酸-硼砂缓冲溶液中在30℃条件下衍生反应5 min后获得稳定的荧光衍生产物.激发波长和发射波长分别为497 nm和509 nm,实现了儿茶酚胺柱前衍生检测,方法的重现性好、灵敏度高.儿茶酚胺的线性相关系数大于0.9970,检出限为5 nmol/L.     

化学物质衍生-同步荧光法测定注射液中γ-氨基丁酸的含量

采用化学物质衍生结合同步荧光法,建立一种检测注射液中γ-氨基丁酸含量的方法.对γ-氨基丁酸的衍生产物进行同步荧光扫描,考察了影响体系荧光强度的因素.最佳实验条件为:8.0×10-3 mol/L硼砂缓冲液(pH=9.6),1.0×10-5 mol/L邻苯二甲醛-2.86×10-5 mol/Lβ-巯基乙醇组合试剂为衍生试剂,衍生时间60min,激发光、发射光通带宽度为5.0nm,λem=455.0nm,Δλ=120.0nm,检测液温度小于25℃.结果表明:在上述条件下获得的同步荧光光谱峰形最好,荧光强度最大.γ-氨基丁酸的线性范围为2.50～50.00μg/L,相关系数为0.999 0,检测限为0.79μg/L.本方法灵敏度高,操作简便,成本低,可用于注射液中γ-氨基丁酸含量的检测.     

柱后碘衍生—高效液相色谱法测定脂必妥片中黄曲霉毒B1的含量

为建立测定脂必妥片中黄曲霉毒素B1含量的高效液相分析法,样品经80％甲醇溶液超声提取后,通过免疫亲合柱净化、柱后碘衍生化,以荧光检测器检测,采用Waters Sunfire C18色谱柱(4.6 mm× 250 mm,5 μm);甲醇—乙腈—水(40∶ 18∶42)为流动相;流速,0.8 mL/min;柱温,25℃;衍生溶液为0.05％的碘溶液,衍生化泵流速,0.3 mL/min,衍生化温度70℃;激发波长λex=360 nm,发射波长λem=450 nm.结果显示,黄曲霉毒素B1在0.0008～ 0.0040 ng(r=0.9999)范围内呈良好的线性关系;回收率为97.13％ (RSD=0.73％),检出限为0.5μg/kg.本方法简便,结果准确可靠,适于测定脂必妥片中黄曲霉毒素B1的含量.     

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.     

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