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1.
2-(5-溴-2-吡啶偶氮)-5-二乙氨基苯酚(5-Br-PADAP)在极谱和伏安分析中的应用已有一些报道。陈林林等曾经研究过Ti(Ⅳ)-5-Br-PADAP络合物在稀H2SO4-H2C2O4溶液中的极谱行为,但灵敏度不高(1.0×10-7mol/L)。我们发现,在pH4.1左右的HAc-NaAc底液中,Ti(Ⅳ)-5-Br-PADAP-NaClO3体系产生一灵敏的极谱吸附催化波,二次导数峰电位在-0.86V(vs.SCE)左右,波形良好,波高稳定,检测限可达4×10-10mol/L。1 实验部…  相似文献   

2.
和厚朴酚的电化学行为及反应机理研究   总被引:3,自引:0,他引:3  
和顾朴酚在0.1mol/L NH3-NH4Cl缓冲溶液(PH9.4)中,用线必 安法得到两个还原峰P1和P2。峰电位分别为EP1=-0.23V和EP2=-1.18V(vs,Ag/AgCl)。用线性扫描与循环伏安法、脉冲极谱法和恒电位库仑法等手段研究体系的电化学行为及其反应机理。实验表明,P1和P2均为不可逆波。P1和P2的电子转移数均为2。和厚朴酚在汞电极上的吸附具有中性分子吸附的特征,吸附符合F  相似文献   

3.
研究了脱氧核糖核酸的极谱伏安行为,在0.1mol.L^-1NH4Cl溶液中DNA产生一良好的极谱峰,峰电位Ep=-1.65V(vs.Ag/AgCl),且峰电流ip与DNA的浓度在4.5*10^-5-3.7*10^-4mol.LO^-1范围内呈线性关系,可望用于DNA的定量分析。  相似文献   

4.
本文比较了Mo(Ⅵ)-1-(2-吡啶基偶氮)-2-萘酚(PAN)与Mo(Ⅵ)-4(2-吡啶基偶氮)间苯二酚(PAR)的极谱性质,讨论它们在作为吸附波试剂时的优缺点,以求得在选择络合剂时的感性和理性认识.本文还报道了Mo(Ⅵ)-PAN-KBrO3吸附催化波体系,最佳实验条件,0.1mol/LHAc--NaAc,pH=4.6,0.01mol/LKBrO3,2.5×10-5mol/LPAN.峰电位为-0.71V(vs.SCE),检出限1×10-9mol/L,线性范围0~6×10-7mol/L  相似文献   

5.
氧氟沙星—镁络合吸附波的研究   总被引:2,自引:0,他引:2  
本文用多种电化学方法研究了氧氟沙星与镁离子的相互作用及其极谱伏安行为,在0.01mo1/L的NH3-NH4C1缓冲溶液中(pH=9.2),氧氟沙星与镁离子络合,产生一灵敏的还原峰,峰电位EP=-1.70V(vs.Ag/AgCl).该峰为不可逆的络合吸附峰,还原峰电流与镁离子浓度在4×10-6~2×10-5mol/L范围内呈良好的线性关系,可望用于镁离子的分析测定.本文还测定了该络合物的络合比,探讨了电极反应机理与络合物结构.  相似文献   

6.
博莱霉素A5的示波极谱行为及测定   总被引:1,自引:0,他引:1  
谭学才  李启隆 《分析化学》1997,25(7):789-791
在0.05mol/L H2SO4支持电解质中,博莱霉素A5出现二个示波极谱导数还原峰,峰电位Ep1=-0.82V和Ep2=-1.08V(vs.SCE)。峰电流ip1比峰电流ip2小得多。ip2与博莱霉素A5的浓度在5.0*10^-8-4.0*10^-6mol/L范围内呈线性关系;检出限为1.0*10^-8用于老鼠血样中博莱霉素A5含量的测定,得到满意的结果,对第二个峰的电化学行为作了初步探讨。  相似文献   

7.
姚德  刘辉 《分析试验室》1994,13(6):68-71
在0.2mol·L^-1NH4Cl-NH3·H2O底液中,(pH为9.26),得到一个极为灵敏的Fe(Ⅲ)-TEA-5-Br-PADAP-H2O2配合吸附催化波,其峰电位为-0.71V(vs.SCE)。铁浓度在1.8×10^-10 ̄5.4×10^-6mol·L^-1范围内与二阶导数波高呈线性关系。对该极谱波的性质进行了研究,证明是一种配合吸附催化波,并成功地应用于各类水样,钒催化剂中微量或痕量铁的  相似文献   

8.
8—氮鸟嘌呤的极谱伏安行为   总被引:4,自引:0,他引:4  
张勇 《分析化学》1998,26(6):729-732
用循环伏安法(CV)、电流采样极诸法(SCP,即TAST)、常规脉冲极谱法(NPP)、微分脉冲极谱法(DPP)、线性扫描伏安法(LSV)、Osteryoung方波伏安法(OSWV)和计时库仑法(CC)等电化学技术研究了抗癌药物8-氮鸟嘌呤(8-azaguanine,guanazolo,简称8-AG)的极谱伏安行为.在 0. 1mol/L H2SO4底液中,8-AG有一良好的还原峰,峰电位(Ep)在-0. 95V(vs.Ag/AgCl,下同)附近,8-AG浓度在4×10-6~8×10-4mol/L范围内.峰高与浓度有良好的线性关系,线性相关系数r=0.9999~0.9910,检出限为1× 10-6mol/L.实验证明了该峰具有吸附性.本文提出了电极反应机理,它包括:酸性介质中8-AG的质子化、质子化的8-AG在汞电极上吸附以及完全不可逆的两电子还原过程.同时用量子化学计算方法(全略微分重叠法即CNDO/2)对8-AG和鸟嘌呤的各原子的净电荷以及Wiberg键级进行了计算,从理论上解释了8-AG的电化学还原机理。  相似文献   

9.
在0.lmo1/LH_2SO_4溶液中,安非拉酮出现一灵敏的示波极谱导数还原波,E_p=-0.80V(vs.SCE),峰高与安非拉酮的浓度在1.0×l0 ̄-7~6.0×1O6mol/L范围内成线性关系,检出限为1.0×10 ̄-7mol/L用于片剂测定,得到满意的结果。用循环伏安法等手段研究体系的极谱和伏安行为,测得吸附量,吸附系数β=5.6×10 ̄-4,吸引因素a=0.49,吸附自由能△G=-27kJ/mol。实验表明,该体系属不可逆吸附波。  相似文献   

10.
在0.1mol/L HAc-NaAc(pH4.50)支持电解质中,淋必治(SPE)有一灵敏的示波极谱导数还原峰,峰电位Ep=-0.98V(vs.SCE)。峰电流与SPE的浓度在2.0×10^-7 ̄8.0×10^-5mol/L范围内呈线性关系,最低检出限为5.0×10^-8mol/L。该法用于注射针剂中SPE含量的测定。,结果良好。文中对SPE的极谱行为、电极过程及反应机理进行了探讨。  相似文献   

11.
王钢  姚修仁 《分析化学》1993,21(1):27-30
在0.020mol/硼砂-0.0030%亚硝基红盐-0.0040%氯化癸基吡啶体系中,镍有一灵敏的络合物吸附波,峰电位-0.55V(υs. Ag/AgCl),线性范围0.2~1600ng/ml,可用于水样和发样的测定。镍与亚硝基红盐形成1:3的二元络合物。络合物在滴汞电极上的吸附,低浓度符合Langmuir吸附等温线,高浓度符合Frumkin吸附等温线。  相似文献   

12.
舒乐安定吸附伏安法的研究   总被引:2,自引:0,他引:2  
Jimenez曾研究了舒乐安定的性质,但灵敏度较低,本文提出了测定痕量舒乐安定的吸附伏安法,在0.1 mol/L NH_3-NH_4Cl溶液(pH 9.3)中,富集电位—0.80 V(us. Ag/AgCl)得一灵敏的舒乐安定还原峰,Ep=—1.05 V,i_p与舒乐安定浓度在3.0×10~(-9)~5.0×10~(-6) mol/L范围内呈线性关系,检测限达1.0×10~(-9)mol/L,并用于试样的测定,用循环伏安法和恒电  相似文献   

13.
Treatment of [Et(4)N][M(CO)(6)] (M = Nb, Ta) with I(2) in DME at -78 degrees C produces solutions of the bimetallic anions [M(2micro-I)(3)(CO)(8)](-). Addition of the tripodal phosphine (t)BuSi(CH(2)PMe(2))(3) (trimpsi) followed by refluxing affords (trimpsi)M(CO)(3)I [M = Nb (1), Ta (2)], which are isolable in good yields as air-stable, orange-red microcrystalline solids. Reduction of these complexes with 2 equiv of Na/Hg, followed by treatment with Diazald in THF, results in the formation of (trimpsi)M(CO)(2)(NO) [M = Nb (3), Ta (4)] in high isolated yields. The congeneric vanadium complex, (trimpsi)V(CO)(2)(NO) (5), can be prepared by reacting [Et(4)N][V(CO)(6)] with [NO][BF(4)] in CH(2)Cl(2) to form V(CO)(5)(NO). These solutions are treated with 1 equiv of trimpsi to obtain (eta(2)-trimpsi)V(CO)(3)(NO). Refluxing orange THF solutions of this material affords 5 in moderate yields. Reaction of (trimpsi)VCl(3)(THF) (6) with 4 equiv of sodium naphthalenide in THF in the presence of excess CO provides [Et(4)N][(trimpsi)V(CO)(3)] (7), (trimpsi)V(CO)(3)H, and [(trimpsi)V(micro-Cl)(3)V(trimpsi)][(eta(2)-trimpsi)V(CO)(4)].3THF ([8][9].3THF). All new complexes have been characterized by conventional spectroscopic methods, and the solid-state molecular structures of 2.(1)/(2)THF, 3-5, and [8][9].3THF have been established by X-ray diffraction analyses. The solution redox properties of 3-5 have also been investigated by cyclic voltammetry. Cyclic voltammograms of 3 and 4 both exhibit an irreversible oxidation feature in CH(2)Cl(2) (E(p,a) = -0.71 V at 0.5 V/s for 3, while E(p,a) = -0.55 V at 0.5 V/s for 4), while cyclic voltammograms of 5 in CH(2)Cl(2) show a reversible oxidation feature (E(1/2) = -0.74 V) followed by an irreversible feature (0.61 V at 0.5 V/s). The reversible feature corresponds to the formation of the 17e cation [(trimpsi)V(CO)(2)(NO)](+) ([5](+)()), and the irreversible feature likely involves the oxidation of [5](+)() to an unstable 16e dication. Treatment of 5 with [Cp(2)Fe][BF(4)] in CH(2)Cl(2) generates [5][BF(4)], which slowly decomposes once formed. Nevertheless, [5][BF(4)] has been characterized by IR and ESR spectroscopies.  相似文献   

14.
Lead is one of the poisonous trace element for human body. It is important to find a way for measuring content of lead. Deternination of lead by electrochemistry is one of a method[1]. In this paper, lead is determined by single-sweep polarography. The absorption behavior of meso-tetra (4-sulfonylphenyl) porphyrin (H2TPPS4) complex with lead ion has also been studied.In Na2B4O7-NaOH solution with pH=l 0.5, the reduction peaks of the ligand are P1 (Ep1=-0.38V), P2 (Ep2=-1.04V), which potentials are obtained vs. S.C.E. When lead ion has been added into above solution. The peak current of P1 and P2 decrease, and a new reduction peak P3 (Ep3=-1.10 V) appears. It shows that the TPPS4-Pb(Ⅱ) complex forms,and this method can be applied to study the complex.  相似文献   

15.
A new complex [Ru(bpy)(2)(bpySH)](PF(6))(2), RuBpySH, has been prepared bearing two anchoring groups for surface attachment, where bpy is 2,2'-bipyridyl and bpySH is 5,5'-bis(mercaptomethyl)-2,2'-bipyridine. Monolayers of RuBpySH have been formed on micro and macro platinum electrodes by spontaneous adsorption from micromolar solutions of the complex in 50:50 v/v water/acetone. The monolayers can be reversibly switched between the Ru(2+) and the Ru(3+) forms. Cyclic voltammetry is well-defined with a peak-to-peak splitting of 30 +/- 5 mV and a full width at half-maximum of 110 +/- 10 mV being observed for scan rates up to 5 V s(-1) where the supporting electrolyte is 0.1 M tetrabutylammonium tetrafluoroborate in acetonitrile. Adsorption is irreversible in this system, and the saturation coverage obtained is 8.1 +/- 0.4 x 10(-11) mol cm(-2) when the complex concentration in the deposition solution is between 10 microM and 1.0 mM. The dynamics of adsorption depend markedly on the bulk concentration and are described in terms of irreversible adsorption. Dry monolayers display luminescence properties similar to those of powder samples of the complex, indicating that the monolayer has characteristics of the solid-state sample rather than the solution sample of the complex. Significantly, efficient electrochemiluminescence is generated using tripropylamine as the coreactant. The rate of electron transfer across the electrode/monolayer interface has been probed using high scan rate cyclic voltammetry. The standard heterogeneous electron-transfer rate constant, k degrees , is 0.9 +/- 0.1 x 10(4) s(-1), and there is weak adsorbate-electrode electronic communication.  相似文献   

16.
The electrochemical characteristics of Haloperidol and related compounds, representative neuroleptics of the butyrophenone family, have been investigated as a function of pH and concentration by direct-current, alternating-current and differential-pulse polarography and cyclic voltammetry at a hanging mercury drop electrode. A single cathodic wave representing an irreversible two-electron reduction is obtained, and its half-wave potential differs from that characteristic of aromatic ketone reduction. Adsorption processes disturb the wave behaviour and an adsorption prewave is observed at high concentrations. Quantitative measurements were successful in the concentration range 1 x 10(-4)-1 x 10(-6)M (0.4 mg/l.), the lower concentration representing the detection limit by differential-pulse polarography.  相似文献   

17.
乙酰胆碱酯酶催化水解产物的电化学行为   总被引:1,自引:0,他引:1  
报道了乙酰硫代胆碱水解产物硫代胆碱在玻碳电极上的电化学行为。以乙酰硫代胆碱作底物,在一定条件下乙酰胆碱酯酶催化底物水解,生成电活性物质硫代胆碱。利用循环伏安法和线性扫描伏安法研究了酶催化水解产物硫代胆碱在玻碳电极上的电化学行为。结果表明:在0.1mol/L的B-R缓冲溶液(pH7.0)中,硫代胆碱有一灵敏的氧化峰,峰电位EP=0.32V(vs.SCE);该体系属具有吸附性的不可逆过程。实验测得电子转移数为2,电极反应速率常数k=0.29s-1。  相似文献   

18.
Voltammetric Investigations on the Oxidation Step of Symmetrical Triazacarbocyanine Dyes in Acetonitrile Solution The oxidation behaviour of twelve symmetrical triazacarbocyanine dyes with different heterocycles in MeCN (containing tetrabutylammonium perchlorate) has been investigated by means of dc-, ac- and cyclic triangular wave voltammetry. The oxidation mechanism has been found to be of the type ec, with the electrochemical step being reversible to irreversible. Oxidation potentials and transfer coefficients have been measured (E1/2 1.60 to 2.12 V vs. Ag/AgCl) and compared with known properties of carbocyanines. The effect of substituents X has been studied on the compounds 1,3-diethyl-2-[3-(1,3-diethyl-5-X-benzimidazolin-2-ylidene)-1-triazeno]-5-X-benzimidazolium tetrafluoroborate ( (1a(X)) and 3-ethyl-2-[3-ethyl-5-X-Δ4-1,3-thiazolin-2-ylidene)-1-triazeno]-5-X-1,3-thiazolium tetrafluoroborate ( 1g(X)) , and ρ-values of 0.425 and 0.565 V, respectively, have been found.  相似文献   

19.
The anionic boron peri-bridged naphthalene derivative, namely dimesityl-1,8-naphthalenediylborate (1), undergoes a hydrolysis reaction to afford dimesityl-1-naphthylborane (2) whose structure has been determined. Upon standing at room temperature in toluene for an extended period of time, 1 undergoes a ring expansion reaction to afford 8,10,11a-trimethyl-7-mesityl-11aH-7-boratabenzo[de]anthracene (3). As shown by its crystal structure, compound 3 constitutes a rare example of a borataalkene and features a carbon-boron double bond of 1.475(6) Angstroms incorporated in a conjugated hexa-1-boratatriene system. The reaction of 1 with 9-chloro-9-borafluorene and 5-bromo-10,11-dihydrodibenzo[b,f]borepin results in the formation of diboranes 4 and 5 which bear two different boryl moieties at the peri-positions of naphthalene. These diboranes have been characterized by multinuclear NMR spectroscopy and X-ray single crystal analysis. The boron center of the borafluorenyl moiety is pi-coordinated to the ipso-carbon of a mesityl group with which it forms a contact of 2.730(3) Angstroms. The cyclic voltammogram of 2 in THF shows a quasi-reversible reduction wave at E(1/2)-2.41 V (vs. Fc/Fc+) corresponding to the formation of the radical anion. In the case of diboranes 4, 5 and 1-(dimesitylboryl)-8-(diphenylboryl)naphthalene (6), two distinct waves are observed at E(1/2)-2.14 and -2.56 V for 4, E(1/2)-2.26 and -2.78 V for 5, and E(1/2)-2.41 and -2.84 V for 6. The first reduction wave most likely indicates the formation of a radical anion in which the unpaired electron is sigma-delocalized over the two boron centers.  相似文献   

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