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1.
魏显有 《分析化学》1995,23(5):502-505
在HCl-NaAc介质(pH2.5)中,用单扫示波极谱法可获得高灵敏的In(Ⅲ)-2-巯基苯骈噻唑(MBT)-7-碘-8-羟基喹啉-5-磺酸(Ferron)三元络合物吸附波,峰电位在一-0.64V(vs.SCE),峰电流与铟浓度在7.0×10^-10mol/L~8.8×10^-7mol/L之间呈线性关系,检出限可达3.0×10^-10mol/L,测得电活性络合物的组成为In(Ⅲ):MBT:1∶1∶  相似文献   

2.
蒙脱土修饰电极上某些神经递质的电化学行为   总被引:7,自引:0,他引:7  
采用不同电化学方法对神经递质多巴胺(DA)在蒙脱土修饰电极上的行为进行了研究,结果发现,蒙脱土修饰膜地DA有明显的富集作用。在PH7.4时,DA强烈地富集在蒙脱土膜内,并显示完成的伏安响应而抗坏血酸(AA)和DAR的代谢产物3,4-二羟基苯乙酸(DOPAC)则无任何响应。采用计时库仑法测定了DA在蒙脱土膜内的表观扩散系数为2.3×10^-9cm^2/s,并计算了异相速率常数为2.7×10^-6cm  相似文献   

3.
镓(Ⅲ)-芦丁体系的吸附伏安行为及其应用于镓(Ⅲ)的测定   总被引:2,自引:0,他引:2  
赵敬中  张立云  孙德志  杨晴 《分析化学》2000,28(12):1546-1548
对镓(Ⅲ)-芦丁体系在悬汞电极上的吸附伏安法作了研究,确字电极过程。在PH5.0的HAc-NaAc缓冲底液中用该体系的1.5阶微分吸附伏安法测定镓,其线性范围是1*10^-10-1*10^-7mol/L;检测限为7.5*10^-11mol/L。用此法测定了粮食中的镓。  相似文献   

4.
在pH4.5的 0.015 mol/L HAc-NaAc介质中,In铟(Ⅲ)-7-(1-苯偶氮)-8-羟基喹啉-5-磺酸钠(BQ)在滴汞电极上于-0.665-0.70 V(vs.SCE)电位处得到络合物的吸附还原波,其一阶导数峰电流I'p与In(Ⅲ)浓度在4.0× 10~(-8)~3.5 × 10~(-6)mol/L范围内呈良好的线性关系,检测限为1.6 × 10~(-8)mol/L In(Ⅲ).应用该法测定了铅粉和氢氧化铝样品中的微量铟,结果令人满意。对电极反应机理进行了探讨。  相似文献   

5.
吸附络合物体系的示波分析   总被引:5,自引:0,他引:5  
In(Ⅲ)在pH457HAcNaAc0.1%VC0.06%HCuP溶液中,用示波计时电位法可获得良好示波图,其切口电位为E=090(Vs.SCE),切口高度与In(Ⅲ)浓度在800×10-7~14×10-5mol/L范围内成正比,检出限可达50×10-7mol/L吸附络合物组成为In(Ⅲ):铜铁试剂(HCup)=1∶1,条件稳定常数为59×103  相似文献   

6.
在0.06mol/L NaAc-HAc pH4.5的缓冲底液中,偶氮氯膦Ⅲ(CPAⅢ)在-0.25V(vs.Ag/AgCl)有一良好的微分脉冲极谱还原波,加入希土(RE)后期峰高电流(ip)降低,轻希土浓度在1×10^-6~6×10^-6moo/L,钇和重希土浓度在2×10^-7~3×10^-6mol/L范围中,ip的降低与浓度呈线性关系,表明CPAⅢ亦是可用的希土极谱分析试剂。实验证明它们是不可  相似文献   

7.
研究了新试剂7-(2,4-二羟基-5-羧基苯偶氮)-8-羟基喹啉-5-磺酸(简称DHCBAQS)与铝(Ⅲ)形成的络合物的荧光性能。在pH4.62的NaAc-HAc体系中形成1∶1型强荧光配合物,其λex=510nm、λem=572nm,铝(Ⅲ)含量在0~0.08mg/L范围内与荧光强度呈线性关系,方法检出限为1.04×10-10mol/L。本方法用于茶叶、淀粉及水样中痕量铝(Ⅲ)的测定。  相似文献   

8.
KeywordIndexVol.7,1996¥//Q,a-Dioxo(ester)ketene(-)10-EPI-a--cyperonediene(7O3)cycledithioacetals(695)2-BenzenimidaZolethiol(9...  相似文献   

9.
镓,铟与酸性铬深蓝络合物吸附波的研究及其应用   总被引:9,自引:0,他引:9  
在醋酸盐缓冲溶液中,用单扫示波极谱法分别获得了镓(Ⅲ)、铟(Ⅲ)与酸性铬深蓝灵敏的络合物吸附波。两个波的峰电位分别为-051V和-063V(vsSCE),镓(Ⅲ)的线性范围为720×10-7~746×10-6mol/L;铟(Ⅲ)为174×10-7~488×10-6mol/L。作者研究了该电极反应机理。该法用于矿石中镓、铟的测定,结果满意。  相似文献   

10.
镓(Ⅲ)-向红菲咯啉络合物极谱吸附波的研究及应用   总被引:2,自引:0,他引:2  
李秀玲  周长利  卢燕  曹伟  杨锋 《分析化学》1998,26(4):451-453
在 PH=4.2的 0.07 mol/L HAc-NaAc介质中,Ga(Ⅲ)-向红菲咯啉络合物在单扫描极谱仪上于-0.98 V(vs.SCE)处产生一灵敏的吸附还原波,其二阶导数波灵敏度高,波形好,峰电流 Ip与 Ga(Ⅲ)在 8.0×10-8~3.0× 10-6mol/L的浓度范围内呈现良好线性关系,检出限为7.0×10-8mol/LGa(Ⅲ)。用该法对粮食中的镓进行了测定,并对电极过程进行了研究。  相似文献   

11.
用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.  相似文献   

12.
Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.  相似文献   

13.
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.  相似文献   

14.
The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.  相似文献   

15.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

16.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.  相似文献   

17.
The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.  相似文献   

18.
A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.  相似文献   

19.
Zhanhui Yang  Shiyi Yang  Jiaxi Xu 《Tetrahedron》2017,73(23):3240-3248
Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.  相似文献   

20.
A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.  相似文献   

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