共查询到20条相似文献,搜索用时 46 毫秒
1.
利用电泳中介微分析通过与邻菲罗啉的络合反应完成了对Fe2+与Cu2+的同时测定。在压差作用下,淌度较小的邻菲罗啉在金属离子区带之前首先进样,加高电压后,两区带电泳在磷酸缓冲液中 (pH=4. 5)混合、反应形成络合物并实现电泳分离。研究了缓冲液pH、试剂和样品区带长度对分离效果的影响。对于Fe2+与Cu2+两离子,方法的检出限(S/N=3)分别为 1. 6和 11μmol/L;线性范围分别为 5. 0×10-6 ~3. 0×10-4 mol/L(r=0. 9979)和 8. 0×10-5 ~3. 0×10-4 mol/L(r=0. 9996)。采用标准矿样验证了测定Fe2+的可行性。 相似文献
2.
四羟基蒽醌修饰活性炭碳糊电极流动注射安培法测定铬(Ⅵ) 总被引:5,自引:0,他引:5
报道了将四羟基蒽醌吸附在稻壳基活性炭上 ,用直接混合法制备成化学修饰电极及其在测定Cr 中的应用。研究表明 ,Cr 的电还原产物Cr 可被该电极吸附 ,产生较灵敏的后行吸附。通过实验考察 ,确定了流动注射安培法测定Cr 的最佳操作条件。支持电解质为 0 .0 6mol/L的H2 SO4,在 - 0 .6V电位下作计时电流法测定 ,该电极对Cr 在 5 .0× 10 -6~ 1.0× 10 -3 mol/L范围内有良好的线性响应 ;检出限为 4 .3×10 -7mol/L ;Mg2 + 、Mn2 + 、Al3 + 和Fe3 + 等 10余种共存离子基本不干扰。每次进样后用底液洗脱 5 0s ,可不必更新电极表面。 相似文献
3.
4.
5.
6.
以8-羟基喹啉作为络合剂,用单扫描极谱仪对微量Fe(Ⅲ)的络合吸附波进行了研究。8-羟基喹啉用量为2×10~(-3)mol/L时,用氢氧化钾溶液调节pH值至碱性条件(pH约为12.0),于-0.37V(vs. SCE)处,有一灵敏的阴极波。Fe(Ⅲ)浓度在2.1×10~(-8)~2.6×10~(-6)mol/L范围内与一阶导数波峰高成线性关系。该法可用于准确测定样品中痕量Fe(Ⅲ)。 相似文献
7.
8.
铁(Ⅲ)-氧氟沙星-SDS三元体系的荧光特性及应用 总被引:2,自引:0,他引:2
在表面活性剂十二烷基硫酸钠(SDS)存在下,铁(Ⅲ)能与氧氟沙星形成络合物而猝灭氧氟沙星分子的内源性荧光,使其荧光强度显著降低,据此,提出了铁(Ⅲ) 氧氟沙星SDS体系测定铁(Ⅲ)的荧光分析新方法。铁(Ⅲ)浓度在2.0×10-8~2.0×10-6mol/L范围内与荧光猝灭值△F成正比,方法的检出限为1.0×10-8 mol/L。该法简单,灵敏度高,选择性好,可直接用于水样和食品中微量铁(Ⅲ)的测定,结果满意。 相似文献
9.
聚酰胺分离富集催化动力学电位法测定痕量钯 总被引:2,自引:0,他引:2
研究了一种以痕量Pd2+为催化剂,邻二氮杂菲作活化剂,并基于铁氰化钾与EDTA之间的配位反应为指示反应的催化动力学电位法。该法基于用氰电极测定反应中释放出来的氰化物,测定钯的线性范围为5.0×10-10~5.0×10-6mol/L,检出限为1.32×10-11mol/L。采用聚酰胺分离富集可以除去干扰离子的影响。该法用于样品中痕量钯的测定,结果满意。 相似文献
10.
双波长分光光度法同时测定水样中的Cr(Ⅲ)和Cr(Ⅵ) 总被引:1,自引:0,他引:1
以EDTA为显色剂,在pH 3.5~4.0,75℃水浴加热条件下,用双波长分光光度法同时测定水中Cr(Ⅲ)和Cr(Ⅵ)。选择测定Cr(Ⅵ)的波长对为352nm和441 nm,测定Cr(Ⅲ)的波长为542 nm,Cr(Ⅵ)的线性范围和检出限分别为0~120 mg/L和0.025 mg/L;Cr(Ⅲ)线性范围和检出限分别为0~140 mg/L和0.007 mg/L。Cr(Ⅵ)和Cr(Ⅲ)加标回收率分别为96.4%~100.4%和99.8%~104.5%。 相似文献
11.
Mathias Getzlaff Joachim Bansmann Gerd Schönhense 《Fresenius' Journal of Analytical Chemistry》1995,353(5-8):743-747
Investigations of the electronic and magnetic properties of oxygen adsorbed on magnetized iron films have been carried out by means of angle and spin resolving photoelectron spectroscopy. Iron, epitaxially grown on W(100) and W(110) crystals, served as the ferromagnetic substrate. Exchange splittings of the O 2px derived level have been detected, demonstrating a magnetic coupling between the chemisorbate and the iron layer. Variations of the exchange splitting have occurred as a function of the oxygen coverage, photon energy, and emission angle. High oxygen exposures have lead to a FeO overlayer at the surface. 相似文献
12.
Mathias Getzlaff Joachim Bansmann Gerd Schönhense 《Analytical and bioanalytical chemistry》1995,353(5-8):743-747
Investigations of the electronic and magnetic properties of oxygen adsorbed on magnetized iron films have been carried out by means of angle and spin resolving photoelectron spectroscopy. Iron, epitaxially grown on W(100) and W(110) crystals, served as the ferromagnetic substrate. Exchange splittings of the O 2px derived level have been detected, demonstrating a magnetic coupling between the chemisorbate and the iron layer. Variations of the exchange splitting have occurred as a function of the oxygen coverage, photon energy, and emission angle. High oxygen exposures have lead to a FeO overlayer at the surface. 相似文献
13.
Novel Fe(III)Fe(III) and Fe(II)Fe(III) complexes [Fe(2)(BBPMP)(&mgr;-OAc)(&mgr;-X)](n)() (1, X = OAc(-), n = 1+; 2, X = OH(-), n = 1+; 3, X = OAc(-), n = 0; 4, X = OH(-), n = 0), where BBPMP(3)(-) is the anion of 2,6-bis[(2-hydroxybenzyl)(2-pyridylmethyl)aminomethyl]-4-methylphenol, and OAc(-) is acetate, were prepared in order to provide models for the active site of purple acid phosphatases (PAPs). Complex 1 was obtained by the reaction of H(3)BBPMP with Fe(ClO(4))(2).6H(2)O in methanol and sodium acetate trihydrate under ambient conditions, while complex 3 was synthesized as described for 1, under an argon atmosphere with low levels of dioxygen. 2 was isolated from 1in acetonitrile by a substitution of the bridging acetate group by hydroxide, while 4 was generated in solution during a spectropotentiostatic experiment on 2, under argon. Complex 1, [Fe(III)(2)(BBPMP)(&mgr;-OAc)(2)]ClO(4).H(2)O, has been characterized by X-ray crystallography. Crystal data: monoclinic, space group P2(1)/n, a = 14.863(5) ?, b = 12.315(3) ?, c = 20.872(8) ?, beta = 90.83(3) degrees, Z = 4. IR, M?ssbauer, magnetic, electronic absorption, and electrochemical properties of 1-3 have been investigated, and some of these properties represent a contribution to the understanding of the dinuclear iron center of PAPs. Complexes 2, [Fe(III)(2)(BBPMP)(&mgr;-OAc)(&mgr;-OH)]ClO(4) (lambda(max) = 568 nm/epsilon = 4760 M(-)(1) cm(-)(1)), and 4 [Fe(II)Fe(III)(BBPMP)(&mgr;-OAc)(&mgr;-OH)] (lambda(max) = 516 nm/epsilon = 4560 M(-)(1) cm(-)(1)), constitute good synthetic analogues for the chromophoric site for the oxidized and reduced forms, respectively, of the enzyme. 相似文献
14.
Houjou H Kanesato M Hiratani K Mandon D 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(18):4576-4583
Novel diiron complexes with an Fe2(mu-OMe)2 core were studied as models of the active site of nonheme iron-containing enzymes. X-ray crystal structures of the complexes showed the existence of two types of ligand folding-parallel and twisted-both of which have four virtually equivalent phenolato groups sticking out from the Fe2O2 rhombic plane. Cyclic voltammetry measurements revealed two or more distinct redox waves in a region of relatively high potential, in addition to known Fe(II)/Fe(III) redox waves in a region of lower potential. These new peaks were assigned to the high-valence state of iron atoms, that is, Fe(III)Fe(IV) and Fe(IV)Fe(IV), resonating with the phenoxyl radical(s). The split width of the redox waves ranged from 0.14 to 0.20 eV, which may be a measure of the electronic interaction of the phenolate groups through the Fe2(mu-OMe)2 core. 相似文献
15.
A new type of thiourea cross-linked chitosan with Fe(III) as template (TCCTS template) was synthesized. The adsorption of Fe(II) and Fe(III) on this TCCTS template was studied. The factors affecting adsorption such as pH and contact time were considered. The results showed that the optimum pH value for adsorption was pH = 5.0 and the adsorption equilibrium time was about 60 min. The adsorption isotherms and kinetics were investigated, and the equilibrium data agreed very well with the Langmuir model and the pseudo second-order model could describe adsorption process better than the pseudo first-order model. Results also showed that TCCTS template was a favourable adsorbent for Fe(II) and Fe(III) in aqueous solution. 相似文献
16.
Apostolova E. S. Tikhonov A. P. Sendyurev O. A. 《Russian Journal of Coordination Chemistry》2002,28(1):38-45
Ab initio calculations using the GAMESS program package in the atomic basis TZV (Fe: (14s, 11p, 6d)/[10s, 8p, 3d]; C, O: (11s, 6p)/[5s, 3p]) were performed with account taken of the correlation with the second-order Möller–Plesset (MP2) perturbation theory to predict a new conformer Fe(CO)4 (with D
4h
symmetry). This conformer has a square planar configuration in the ground singlet electronic state and is a mild electrophile produced by dissociation of Fe(CO)5 along the axial Fe–C bond. The process of nucleation of iron nanoparticles Fe(CO)5 + Fe(CO)4 Fe2(CO)9 is supposed to occur in two stages. The first stage is an orbital-controlled reaction which should be monitored as an increase in medium polarity and temperature. It should proceed with participation of only one of the stable conformers of the nucleophile Fe(CO)5, namely, a mild conformer with square-pyramidal structure (C
4v
) rather than a hard but energetically more advantageous conformer with trigonal–bipyramidal structure (D
3h
). The structure of a prereaction complex was discussed. 相似文献
17.
Fe(VI) batteries based on unusual ferrate cathodic charge storage have been studied for quite a few years. So far, a class of Fe(VI) compounds have been successfully synthesized and studied as the cathodic materials in both alkaline and nonaqueous battery systems. This paper provides a summary of the syntheses of a range of Fe(VI) cathodes including the alkali Fe(VI) salts Li2FeO4, K x Na(2?x)FeO4, K2FeO4, Rb2FeO4, Cs2FeO4, as well as alkali earth Fe(VI) salts CaFeO4, SrFeO4, BaFeO4, and a transition metal Fe(VI) salt Ag2FeO4. Two synthesis routes summarized in this paper are the solution phase synthesis and the solid-state synthesis. Preparation of coating-stabilized (coated with KMnO4, SiO2, TiO2, or ZrO2) Fe(VI) cathodes and preparation of thin-film reversible Fe(VI/III) cathodes are also presented. Fe(VI) analytical methodologies summarized in this paper include Fourier transform infrared spectrometry, titrimetric (chromite), ultraviolet-visible spectroscopy, X-ray diffraction, inductively coupled plasma spectroscopy, Mössbauer spectrometry, potentiometric, galvanostatic, and cyclic voltammetry. Cathodic charge transfer of Fe(VI) is also briefly presented. 相似文献
18.
19.
Portius P Yang J Sun XZ Grills DC Matousek P Parker AW Towrie M George MW 《Journal of the American Chemical Society》2004,126(34):10713-10720
The photochemistry of Fe(CO)5 (5) has been studied in heptane, supercritical (sc) Ar, scXe, and scCH4 using time-resolved infrared spectroscopy (TRIR). 3Fe(CO)4 ((3)4) and Fe(CO)3(solvent) (3) are formed as primary photoproducts within the first few picoseconds. Complex 3 is formed via a single-photon process. In heptane, scCH4, and scXe, (3)4 decays to form (1)4 x L (L = heptane, CH4, or Xe) as well as reacting with 5 to form Fe2(CO)9. In heptane, 3 reacts with CO to form (1)4 x L. The conversion of (3)4 to (1)4 x L has been monitored directly for the first time (L = heptane, kobs = 7.8(+/- 0.3) x 10(7) s(-1); scCH4, 5(+/- 1) x 10(6) s(-1); scXe, 2.1(+/- 0.1) x 10(7) s(-1)). In scAr, (3)4 and 3 react with CO to form 5 and (3)4, respectively. We have determined the rate constant (kCO = 1.2 x 10(7) dm3 mol(-1) s(-1)) for the reaction of (3)4 with CO in scAr, and this is very similar to the value obtained previously in the gas phase. Doping the scAr with either Xe or CH4 resulted in (3)4 reacting with Xe or CH4 to form (1)4 x Xe or (1)4 x CH4. The relative yield, [(3)4]:[3] decreases in the order heptane > scXe > scCH4 > scAr, and pressure-dependent measurements in scAr and scCH4 indicate an influence of the solvent density on this ratio. 相似文献
20.
The action of ozone on a suspension of Fe(III) hydroxide in alkaline solutions was studied by the spectrophotometric method.
A partial conversion of Fe(III) to Fe(VI) is observed at Fe(III) concentrations exceeding 2 mmol l−1. The tenfold increase of the initial Fe(III) concentration raises the Fe(VI) yield by a factor of 2–3. The mechanism of the
process includes the decomposition of ozone with the formation of ozonide ions, which oxidize Fe(III) up to Fe(IV), Fe(V),
and Fe(VI) in parallel with their conversion to O2− and HO2−. Fe(VIII) is not formed. 相似文献