Antilg de／dt—E曲线上的示波极谱滴定法

在示波极谱滴定中,当去极剂切口位于示波极谱图|dE/dt|的最大值附近时,利用Antilg dE/dt～E示波图来指示滴定终点能使终点变化更为敏锐。原来较难进行滴定的一些体系现在可用这种方法滴定。在50Hz的交流电频率下,用氨羧络合剂滴定了Cd~(2+)、Pb~(2+)、Zn~(2+)、Co~(2+),滴定结果符合分析要求。非线性放大还可应用于以dE/dt～E示波图的扩张或收缩来指示滴定终点的示波极谱滴定法及以荧光电位线的伸长或收缩来指示滴定终点的示波电位滴定法,以提高终点变化的敏锐性。以亚硝酸钠滴定对氨基苯磺酸为例说明了这一方法的可行性。     

交流示波极谱滴定法

用交流示波极谱曲线(dE/dt)=f(E)上切口的出现或消失来指示滴定终点的容量分析方法称为交流示波极谱滴定法,简称示波极谱滴定。     

玻碳电极上的倒数示波沉淀滴定法

1 引言 近年来示波滴定技术取得了很大的发展,主要体现在两个方面,一方面各种新仪器的研制,使得滴定的灵敏度大大提高,从经典的dE/dt—E曲线发展到i_f—E曲线及倒数示波计时电位曲线;另一方面极化电极也从汞膜电极发展为固体电极,由于汞膜电极的电位仅在0～—2V之间变化,限制了其应用范围固体电极能克服     

交流示波极谱滴定的研究(ⅩⅢ)——有机碱及有机酸盐类药物在水溶液中的中和滴定

本文用交流示波极谱中和滴定技术,在水溶液中直接滴定有机碱和有机酸的盐类药物,简便、快速、准确。     

示波微分伏安滴定法

对示波伏安滴定装置进行了改进;提出了示波微分伏安滴定法;用EDTA及EGTA滴定了Zn~(2+)、Ga~(2+)、Cd~(2+)、Ni~(2+)和Co~(2+)等离子。实验结果表明:新方法灵敏度高、准确性好。     

示波极谱滴定的研究 ⅩⅩⅩⅡ.金电极上的示波极谱滴定法

本文研究了用微金电极为工作电极的示波极谱滴定法。在同样的条件下,用金电极时某些离子如Co~(2+)和Ni~(2+)能产生敏锐的切口,而用铂电极时无切口。用两个相同的微铂电极时,EDTA和某些有机物质可以有灵敏的切口,但用金电极时无切口。微金电极能用于络合、沉淀和氧化还原滴定。这时Mn~(2+),Fe~(2+),Co~(2+),Ni~(2+),Hg~(2+),和Cu~(2+)有灵敏的切口,能用于示波极谱滴定。滴定结果较好,标准偏差不大于0.12％。     

两Ag-TPB电极上的零电流示波双电位滴定法

将银片(或碳棒、铂片等)依次浸入Na-TPB及AgNO_3溶液中,得到用于示波电位滴定的Ag-TPB电极。在这种电极上进行双电位滴定。并用示波器直接指示⊿E的变化,确定滴定终点。方法简便灵敏,且可用于药物分析。     

双修饰电极零电流示波双电位滴定的研究——混合酸的连续滴定

本文采用双聚苯胺修饰电极进行示波双电位滴定,用示波器直接指示△E的变化,以示波器荧光屏上荧光点最大位移指示终点。方法简便、快速、直观,用于乙二醛母液中混合酸的连续滴定,结果满意。     

有机螯合沉淀剂作为交流示波极谱滴定剂的研究——DDTC滴定铜和镉

二乙基二硫代氨基甲酸盐(DDTC)是分析化学中常用的有机螯合沉淀剂。但它至今还不能直接在水溶液中用作视式滴定剂。Wickbold曾报导用DDTC萃取滴定Cu~(2+)、Cd~(2+)等重金属离子。但要耗用大量的具有刺激性气味的有机溶剂,操作也较麻烦。DDTC虽在安培滴定、电位滴定等一些须用作图法确定终点的分析方法中得到了应用,但不及交流示波极谱滴定法直观、简便。     

交流示波极谱滴定的研究(ⅩⅩⅤ)——亚硝酸钠示波极谱滴定法

本文报导了亚硝酸钠示波极谱滴定法在一系列无机、有机和药物分析方面的应用,滴定了十八种物质,本法具有终点直观、简便快速和干扰较少等特点。     

示波分析在中国的发展：Ⅰ.示波分析法

示波分析是在我国新近发展起来的电分析新领域，它有十大类技术：示波计时电位法，改进的示波计时电位法，倒数示波计量电位法，示波电位法，示波伏安８法。示波分析包括示波滴定和示波测定两大分支。本文综述示波分析的方法和特点。     

双[2-(2'-苯氧基)苯并恶唑]二吡啶合锰(II)配合物的研究

X射线晶体结构分析结果表明, 标题化合物晶体(C36H26MnN4O4)属单斜晶系, 空间群为P21/a, a=0.9833(3), b=1.8646(3),c=0.9449(1)nm, Z=2, 最终因子Rw=0.057。利用热重分析对配合物晶体两步热分解过程进行了非等温热力学研究, 探讨了反应的可能机理, 得到其相应的动力学参数。第一步非等温动力学方程为: dα/dt=A.exp(-E/RT).2(1-α)^1^/^2, 第二步: dα/dt=A.exp(-E/RT).3/2(1-α)[-ln(1-α)]^1^/^3。     

MgO－B_2O_3－MgCl_2－H_2O体系与盐酸滴定反应的研究

ＭｇＯ－Ｂ２Ｏ３－ＨｇＣｌ２－Ｈ２Ｏ是含硼盐湖日晒浓缩盐卤的典型体系，它与盐酸反应生成硼酸，是从天然浓缩盐卤中制取硼酸的工艺基础，以量热滴定法和ｐＨ滴定法研究该反应，结果表明，析出硼酸的反应分两步进行；合成盐卤中硼酸盐可以用ＭｇＢ２ｎＯ（３ｎ＋１）（ｎ＝１，２，３）综合统计形式来表示；天然浓缩盐卤中硼酸盐可以用四硼酸镁的统计形式进行表示．     

几种含芯电子相关能修正的G2和G2(ACI)方法

针对冻结芯电子近似,在MP2/6-311G(d,p)级别上对G2、MP2/6-311G(d)和MP2/6-311G(d,p)级别上对G2(QCI)方法进一步考虑了芯电子相关能修正,尝试建立了G2(fu2)、G2(QCI/ful)和G2(QCI/fu2)方法。G2-l test set 的反应能量计算结果表明,这些方法进一步减小了经验修正量;G2(QCI/ful)和G2(QCI/fu2)也比G2(QCI)的总体精度有所提高;但G2(fu2)在G2基础上,总体精度没有改善。G2(fu2)、G2(QCI/ful)和G2(QCI/fu2)计算G2-l test set反应能量的平均绝对偏差分别为5.11、4.74和4.81kJ mol-1,G2和G2(QCI)分别为5.09和4.97kJ mol-1.     

Structures and bonding of the sandwich complexes [Ti(eta5-E5)2]2- (E = CH,N, P,As, Sb): a theoretical study

Quantum chemical calculations using gradient-corrected DFT at the BP86/TZ2P level of the compounds [Ti(eta(5)-E(5))(2)](2)(-) (E = CH, N, P, As, Sb) are reported. The nature of the metal-ligand bonding has been analyzed with an energy decomposition method, and the results are compared with [Fe(eta(5)-E(5))(2)]. The bonding in both series of complexes is more covalent than electrostatic. The energy decomposition analysis shows that the dominant orbital interactions in the negatively charged titanium species come from the (e(2)') Ti --> [(eta(5)-E(5))(2)](2)(-) back-donation (delta bonding) while the covalent bonding in the iron complexes come mainly from (e(1)' ') (Cp(-))(2) --> Fe(2+) donation (pi bonding). The nature of the metal-ligand interactions does not change very much for different ligands cyc-E(5) within the two series of compounds. The calculated bond dissociation energies for breaking one metal-ligand bond of the molecules [Ti(eta(5)-E(5))(2)](2)(-) shows for E the order P > As > Sb > N > CH. The central message of this work is that the complexes [Ti(eta(5)-E(5))(2)](2)(-) are delta bonded molecules.     

倒数示波计时电位滴定新技术

倒数交流示波极谱具有抑制充电电流、突出电解电流的优点,利用(dE/dt)~(-1)-E曲线上去极剂峰的突然消失或出现指示滴定终点的方法称作倒数示波计时电位滴定法.由运算放大器组装的模拟电子线路可以对(dE/dt)~(-1)-E曲线进行反馈、反对数及微分处理,从而获得各种类型的倒数示波计时电位曲线(图1),以进一步提高滴定的灵敏度。     

Multistep nucleophilic substitution of the halogen atom in 2-halo-2-alkenals

pso-Substitution of the halogen atom in 2-halo-2-alkenals under the action of secondary amines proceedsvia three consecutive steps: addition, nucleophilic substitution, and -elimination (the Ad_N-S_N-E mechanism). The main intermediates arising in the reactions of 2-chloropropenal and 2-chloro-2-butenal with piperidine were detected by NMR spectroscopy. A general scheme of the reaction is proposed.Translated fromIzvestiya Akademii. Seriya Khimiicheskaya, No 1.pp. 139–142.January, 1996.     

不同类型探针对免疫层析方法的分析灵敏度影响研究

为研究不同类型探针对免疫层析方法的分析灵敏度影响,该研究以17β-雌二醇(17β-E2)为检测对象,采用磁性纳米材料标记7μg/mL的17β-E2单克隆抗体(检测抗体)制备了传统探针,采用磁性纳米材料分别标记5μg/mL的17β-E2单克隆抗体和5μg/mL的羊抗鼠IgG多克隆抗体(第二抗体)制备了配对探针,采用磁性纳米材料标记14μg/mL的羊抗鼠IgG多克隆抗体制备了间接探针。然后,基于这3种不同类型的探针,分别建立了17β-E2的免疫层析快速检测方法,并对3种17β-E2免疫层析方法的检测灵敏度进行比较。结果显示,基于传统、配对和间接探针的免疫层析方法对17β-E2的检出限分别为1、0.5、0.2 ng/mL,其中基于间接探针的免疫层析方法灵敏度最高,与基于传统探针和配对探针的免疫层析方法相比,检出限分别降低了5倍和2.5倍。该研究刷新了传统免疫层析方法中探针必须是信号材料标记检测抗体的认知,可为其他食品安全危害因子的免疫层析快速检测研究提供有价值的参考。     

Stereoretentive elimination and trans-olefination of the dicationic dipalladium moiety [Pd2Ln]2+ bound on 1,3,5-trienes

The reaction of [Pd(2)(CH(3)CN)(6)][BF(4)](2) (1) with 1,3,5-hexatriene, 1,6-diphenyl-1,3,5-hexatriene (DPHT), or 2,2,9,9-tetramethyl-3,5,7-decatriene (DBHT) afforded bi-eta(3)-allyldipalladium complexes 3, 4, or 5. The reaction of 1 and DBHT proceeded in a stereospecific (syn) manner when the reaction was carried out in CD(2)Cl(2) under aerobic conditions, while a mixture of two diastereomers was formed under N(2) atmosphere. The two diastereomers (5-E,Z,E-antifacial and 5-E,E,E-antifacial) formed from DBHT were isolated, and the structure of 5-E,Z,E-antifacial, which was kinetically formed from the reaction of 1 and (E,E,E)-DBHT, was determined by X-ray diffraction analysis. Addition of phosphine ligands (PPh(3) or dppm) to the dinuclear adduct 5-E,Z,E-antifacial or 5-E,E,E-antifacial in acetonitrile resulted in the stereospecific (syn) elimination of [Pd(2)(PPh(3))(2)(CH(3)CN)(4)][BF(4)](2) (2) or [Pd(2)(dppm)(2)(CH(3)CN)(2)][BF(4)](2) (6). During the PPh(3)-induced dinuclear elimination, the phosphine adducts 7 that retain bi-eta(3)-allyldipalladium structure were observed initially. The phosphine adduct generated from 5-E,E,E-antifacial was isolated and structurally characterized by X-ray diffraction analysis. The reaction of 1 and DPHT in CH(2)Cl(2) afforded unique dipalladium sandwich compounds [Pd(2)(mu-eta(3):eta(3)-DPHT)(2)][BF(4)](2) (8). Interconversion between the sandwich complexes and half-sandwich complexes occurred in a stereoretentive manner. The structure of the sandwich complex 8-E,Z,E formed from 4-E,E,E-antifacial and (E,Z,E)-DPHT was determined by X-ray diffraction analysis. Transfer of the dipalladium moiety [Pd(2)(CH(3)CN)(4)](2+) from DPHT ligand of 4-E,E,E-antifacial onto DBHT ligand proceeded in a stereoretentive manner. The observed stereoretentive dinuclear process is featured by the pairwise behavior of two palladium atoms sitting on the triene pi-plane. In the dinuclear elimination, the two Pd atoms that are initially in the divalent state and bound on the opposite faces (antifacial) come to the synfacial positions to form a Pd-Pd bond prior to dissociation. These results represent the unique property of conjugated olefin as the multidentate ligands for metal-metal moieties.