Simultaneous Polarographic Determination of Iron (II) and Iron (III) in Coal Mine Waste Water

Abstract

Polarography with a sodium carbonate-oxalic acid supporting electrolyte was used to determine both Fe(II) and Fe(III) simultaneously in actual coal mine water samples. The average relative percent error was 2.2% for Fe(II) and 2.1% for Fe(III) over a range of 10 to 500 ppm. In actual mine water the Fe(II) content was highest where the mine water emerged. As the water moved down stream from the source of pollution Fe(II) decreased and Fe(III) concentration increased as Fe(II) was oxidized to Fe(III) by oxygen. This was accompanied by a decrease in pH. Further down the stream Fe(III) started to precipitate and then its concentration steadily decreased.     

Nonstabilized Alkyl Complexes and Alkyl-Cyano-Ate Complexes of Iron(II) and Cobalt(II) as New Reagents in Organic Synthesis

Alkyl transition metal reagents are being increasingly used for alkylations in organic synthesis. They have various advantages over alkyllithium and alkyl-magnesium reagents including higher selectivity, lower basicity, and—as long as the transition metal is not in its highest oxidation state—their willingness to undergo oxidative addition with electrophiles. Alkyl derivatives of Fe^II and Co^II, which are not stabilized by special ligands but still can be easily handled, are in many cases superior to the well-known alkyl–Cu^I and -Mn^II reagents and can also undergo unexpected reactions. The introduction of alkyl-cyanoate complexes of Fe^II and Co^II, the cyanide ligands of which (in contrast to neutral π-acidic ligands) do not reduce the reactivity, has led to further advances. Reaction mechanisms will be discussed and comparisons will be made with alkylating reagents containing Cu^I, Mn^II, Ni^II, or Ti^IV as well as with Pd-catalyzed coupling reactions. Furthermore, it will be shown that super-ate Fe^II complexes are almost certainly the reactive species in highly selective catalytic alkylations.     

Iron(III)‐Complexes Engaged in the Biochemical Processes in Seawater. II. Voltammetry of Fe(III)‐Malate Complexes in Model Aqueous Solution

Characteristics of iron(III) complexes with malic acid in 0.55 mol L^?1 NaCl were investigated by voltammetric techniques. Three iron(III)‐malate redox processes were detected in the pH range from 4.5 to 11: first one at ?0.11 V, second at ?0.35 V and third at ?0.60 V. First process was reversible, so stability constants of iron(III) and iron(II) complexes were calculated: log K₁(Fe^III(mal))=12.66±0.33, log β₂(Fe^III(mal)₂)=15.21±0.25, log K₁(Fe^II(mal))=2.25±0.36, and log β₂(Fe^II(mal)₂)=3.18±0.32. In the case of second and third reduction process, conditional cumulative stability constants of the involved complexes were determined using the competition method: log β(Fe(mal)₂(OH)_x)=15.28±0.10 and log β(Fe(mal)₂(OH)_y)=27.20±0.09.     

邻菲啰啉计算光度法同时测定生物浸出样品中Fe（Ⅱ）和Fe（Ⅲ）

邻菲啰啉光度法常用于Fe（Ⅱ）测定,但受到试样中Fe（Ⅲ） 对测定的影响,因此不能直接用于生物浸出样品中Fe（Ⅱ）和Fe（Ⅲ） 的同时测定. 为此,基于Fe（Ⅱ）邻菲啰啉特征吸收曲线以及混合铁中Fe（Ⅲ） 对Fe（Ⅱ）测定的线性影响关系,建立了基于Fe（Ⅱ）和全铁同时测定Fe（Ⅱ）和Fe（Ⅲ）的计算光度法,并研究了生物浸出样品中典型金属离子（Cu²⁺、Ni²⁺、Cd²⁺、Co²⁺）以及试样溶解与储放对测定的影响.方法可准确地测定含铁次生矿物和生物浸出液中铁价态组成,应用于生物浸出矿渣、细胞表面中常量或微量的Fe（Ⅱ）和Fe（Ⅲ） 组成分析,具有简便快速的特点.     

邻菲啰啉计算光度法同时测定生物浸出样品中Fe（Ⅱ）和Fe（Ⅲ）

邻菲哕啉光度法常用于Fe（Ⅱ）测定,但受到试样中Fe（Ⅲ）对测定的影响,因此不能直接用于生物浸出样品中Fe（Ⅱ）和Fe（Ⅲ）的同时测定．为此,基于Fe（Ⅱ）邻菲哕啉特征吸收曲线以及混合铁中Fe（Ⅲ）对Fe（Ⅱ）测定的线性影响关系,建立了基于Fe（Ⅱ）和全铁同时测定Fe（Ⅱ）和Fe（Ⅲ）的计算光度法,并研究了生物浸出样品中典型金属离子（Cu^2＋、Ni^2＋、Cd^2＋、Co^2＋）以及试样溶解与储放对测定的影响．方法可准确地测定含铁次生矿物和生物浸出液中铁价态组成,应用于生物浸出矿渣、细胞表面中常量或微量的Fe（Ⅱ）和Fe（Ⅲ）组成分析,具有简便快速的特点．     

O-Tolyldithiocarbonate Complexes of Iron(II) and Iron(III)

Abstract

Reactions of O-tolyldithiocarbonate ligands, (o-, m-, and p-CH₃C₆H₄O)CS₂Na, with anhydrous FeCl₂ (1:2 molar ratio) and with FeCl₃ (1:1 and 1:3 molar ratio) yielded the complexes [{(CreO)CS₂}₂Fe] and [{(CreO)CS₂}_nFeCl_3–n] (Cre = o-, m-, and p-CH₃C₆H₄; n = 1 and 3), respectively. These complexes were reacted with nitrogen and phosphorus donor ligands in dichloromethane, which afforded the adducts corresponded to [{(CreO)CS₂}₂Fe.xL] and [(CreO)CS₂FeCl₂.xL] {x = 1, L = N₂C₁₂H₈; x = 2, L = NC₅H₅, P(C₆H₅)₃}. Elemental analyses and IR, UV-visible, and mass spectroscopic and magnetic studies indicated bidentate mode of bonding by dithiocarbonate ligands leading to sixcoordination around the iron atom as a consequence of Fe…Fe interaction in the complexes [{(CreO)CS₂}₂Fe] and [(CreO)CS₂FeCl₂]. The complexes exhibited antifungal activity. The fungicidal activity of the complexes has been tested by poisoned food technique using fungi Fusarium sp.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental resource: Antifungal Activity.     

Speciation of Fe(III) and Fe(II) in water samples by liquid–liquid extraction combined with low-temperature electrothermal vaporization (ETV) ICP-AES

The use of 1-phenyl-3-methyl-4-benzoylpyrazolone (PMBP) as extractant for separation of Fe(III) and Fe(II) and low-temperature vaporization of the Fe(III)–PMBP chelate into ICP-AES for their speciation analysis was investigated. The factors affecting the formation of Fe(PMBP)₃ chelate and its vaporization behavior were investigated in detail. PMBP was used not only as the extractant for the separation of Fe(III) and Fe(II) but also as the chemical modifier for the low-temperature ETV-ICP-AES determination of iron. Under the optimized conditions, the detection limit for iron(III) and iron(II) are both 3.2?ng/mL, with relative standard deviations of 3.9 and 4.5%, respectively. The proposed method was applied to the determination of trace iron in biological standard reference materials and the species in East Lake water samples, and the results obtained were satisfactory.     

Iron(II) and Iron(III) Perchlorate Complexes of Ciprofloxacin and Norfloxacin

The reactions of ciprofloxacin (CIP) and norfloxacin (NOR) with iron(II) and iron(III) perchlorate have been investigated. The optical spectra support the formation of four complexes for each oxidation state with 1 : 1, 1 : 2, 1 : 3 and 1 : 4 metal to ligand molar ratios. The electrical conductivity and magnetic susceptibility measurements show that the isolated complexes are high spin and the Fe(ClO 4 ) 2 and Fe(ClO 4 ) 3 complexes behave as 1 : 2 and 1 : 3 electrolytes, respectively. The IR spectra indicate that CIP and NOR bind to the iron ion as bidentate ligands through the carbonyl oxygen atom and one of the oxygen atoms of the carboxylate group.     

Fe(III)Fe(III) and Fe(II)Fe(III) Complexes as Synthetic Analogues for the Oxidized and Reduced Forms of Purple Acid Phosphatases

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.     

In situ speciation of trace Fe(II) and Fe(III) in atmospheric waters by the FZ method coupled to GFAAS analysis

Two procedures to characterise atmospheres in piggeries are presented. The first allows delocalised sensorial analysis by trapping volatiles from pig shed emissions in a lipid phase. followed by laboratory analysis of their odour characteristics. The second procedure provides instrumental odour signatures of atmospheres. The volatile compounds are concentrated by solid-phase microextraction (SPME). and analysed directly by mass spectrometry without a chromatographic step (SPME-MS). The information supplied by the two analysis methods proved rich and consistent for the 42 piggeries analysed. In addition. the odour signatures allowed a good estimation of the key dimensions of the odour of the lipid phases. This result indicates that SPME-MS is a promising instrumental method to estimate the degree of odour nuisance in livestock buildings.     

A New Type of Anionic Framework in Microporous Potassium Iron(II) Phosphate K[Fe(PO4)]

A new iron(II) orthophosphate K[Fe(PO₄)] has been obtained by hydrothermal synthesis and its crystal structure was determined by single‐crystal X‐ray diffraction: space group P2₁/n, Z = 8, a = 9.6199(10), b = 8.6756(8), c = 10.8996(13) Å, β = 115.577(8)° at 193 K, R = 0.023. Fe^II shows coordination numbers (CN) 4 (distorted tetrahedral) and CN 5 (distorted trigonal bipyramidal). The [FeO₄] and [FeO₅] units form together with the [PO₄] tetrahedra a microporous 3D para‐framework with open channels along the a and b directions. The potassium ions positioned in the channels show CN 7 and 8. The structural relations within the morphotropic row of non‐isotypic K[M(PO₄)] structures (M = Zn, Ni, Mn, Fe) are discussed on the basis of common basic structural units.     

Iron(II) and iron(III) complexes containing ethynyl thiophene fragments

The synthesis of the new complexes Cp*(dppe)FeCC2,5-C₄H₂SR (Cp* = 1,2,3,4,5-pentamethylcyclopentadienyl; dppe = 1,2-bis(diphenylphosphino)ethane; 2a, R = CCH; 2b, R = CCSi(CH₃)₃; 2c, R = CCSi(CH(CH₃)₂)₃; 3a, R = CC2,5-C₄H₂SCCH; 3c, R = CC2,5-C₄H₂SCCSi(CH(CH₃)₂)₃) is described. The ¹³C NMR and FTIR spectroscopic data indicate that the π-back donation from the metal to the carbon rich ligand increases with the size of the organic π-electron systems. The new complexes were also analyzed by CV and the chemical oxidation of 2a and 3c was carried out using 1 equiv of [Cp₂Fe][PF₆]. The corresponding complexes 2a[PF₆] and 3c[PF₆] are thermally stable, but 2a[PF₆] was too reactive to be isolated as a pure compound. The spectroscopic data revealed that the coordination of large organic π-electron systems to the iron nucleus produces only a weak increase of the carbon character of the SOMO for these new organoiron(III) derivatives.     

Determination of Iron(II) in Pharmaceuticals Using Chlorpromazine Hydrochloride as a Redox Indicator

Abstract

Titrimetric method for the determination of (1–100) mg/L iron(II) as pure solutions and in its dosage forms was investigated and found to offer an improvement in ease, speed and accuracy. This method is based on the direct visual titration of iron(II) with ceric amnonium sulphate and employs chlorpromazine hydrochloride in a mixture of sulphuric and phosphoric acids as a redox indicator.

An interference study is carried out for the differant acids and cations. Data obtained for sevceral pharmaceuticals are reported and compared with those obtained potentiometrically. Formal redox potential was determined to be 285 mv.     

Spectrophotometric Determination of Iron(III) as Azide Complexes in Aqueous Tetrahydrofuran

Abstract

A simple, sensitive and alternative method for the spectrophotometric determination of iron(III) has been established. The procedure is based on the formation of iron-azide complexes in 60% (v/v) tetrahydrofuran/ water medium. The high sensitivity obtained in this method is due to the use of an interesting absorption band not previously reported in the literature. In the recommended conditions, absorbances for the ferric complexes are measured at 400 nm where the molar absorptivity is 1.52 × 10⁴ 1 mol^?1 cm^?1. The organic solvent used increases the sensitivity and the stability of the measurements. The precision is shown by the average deviation of about 0.3%. This system obeys Beer's law and is suitable for iron(III) determination in the concentration range from 0.6 to 3.2 mg 1^?1 (ppm). The best experimental conditions were determined studying the different factors involved. The influence of various diverse ions was also studied.     

Determination of Fe(II), Fe(III) and Fetotal in thermal water by ion chromatography spectrophotometry (IC-Vis)

Determination of iron speciation in water is one of the major challenges in environmental analytical chemistry. Here, we present and discuss a method for sampling and analysis of dissolved Fe(II), Fe(III), and Fe_total concentrations in natural thermal water covering a wide range of temperature, pH, chemical composition, and redox conditions. Various methods were tried in the collection, preservation, and storage of natural thermal water samples for the Fe(II) and Fe(III) determinations, yet the resultant Fe speciation determined was often found to be significantly affected by the methodology applied. Due to difficulties in preserving accurate Fe speciation in natural samples for later laboratory analysis, a field-deployed on-site method using ion-chromatography and spectrophotometry was developed and tested. The IC-Vis method takes advantage of ion chromatographic separation of Fe(II) and Fe(III), followed by post-column colour reaction and spectrophotometric detection, thus allowing analysis of Fe(II) and Fe(III) in a single 15-minute run. Additionally, Fe_total can be determined after sample oxidation. The analytical detection limits are ~2 µg L^?1 (LOD) using 200–1000 µL injection volumes and depend on the blank and reagent quality. The power of this method relies on the capability to directly determine a wide range of absolute and relative concentrations of Fe(II) and Fe(III) in the field. The field-deployed IC-Vis method was applied for the determination of Fe(II) and Fe(III) concentrations in natural thermal water with discharge temperatures ranging from 12°C to 95°C, pH between 2.46 and 9.75, and Fe_total concentrations ranging from a few μg L^?c up to 8.3 mg L^?1.     

Determination of Fe(II) and H2O2 in Atmospheric Liquid Water by Peroxyoxalate Chemiluminescence

Abstract

The chemiluminescence reaction of oxygen with bis(2,4,6-trichlorophenyl)oxalate (TCPO) in the presence of Fe(II) has been investigated under the analytical and mechanistic point of view. Its suitability for the determination of Fe(II) as well as H₂O₂ in atmospheric liquid water by using a new static fiberoptic luminometer (FOL) and a flow-injection analysis (FIA) system is demonstrated. Results obtained so far suggest, that chemiluminescence is generated by superoxide ion (O₂ ^?) produced by autoxidation of Fe(II) through dissolved oxygen. The analytical method based on this reaction shows high sensitivity and detection limits below 100 nM Fe(II). Its application to rain water analysis indicates that Fe(II) and H₂O₂ may be coexistent in the atmospheric liquid phase.     

分光光度法测定豆类中铁的含量(Ⅱ)

豆类无污染,无农药残毒,营养丰富,具有特殊风味,并且很多豆类还有医疗保健作用.用分光光度法直接测定了豆类中铁的含量,方法简便快速准确,对指导人们合理食用豆类补铁及进一步开发豆类提供了可靠的理论依据.     

分光光度法测定野菜中铁的含量(Ⅲ)

野菜无污染、无农药残毒,营养丰富,具有特殊风味,并且很多野菜还有医疗保健作用.用分光光度法直接测定了野菜中铁的含量,方法简便快速准确,对指导人们合理食用野菜进行补铁及进一步开发野菜提供了可靠的理论依据.     

Response of a copper(II) and iron(III) ion-selective electrode bielectrode array in saline media

A bielectrode array comprising a jalpaite membrane (i.e., Ag_1.5Cu_0.5S) copper(II) ion-selective electrode (ISE) and chalcogenide glass membrane (i.e., Fe_2.5(Se₆₀Ge₂₈Sb₁₂)_97.5) iron(III) ISE has been assembled by individually wiring each solid-state sensor into a single electrode body. Furthermore, a dual metal ion buffer calibration standard incorporating copper(II) and iron(III) coordinating ligands to regulate the levels of free copper(II) and iron(III) in the buffer has been developed to enable simultaneous calibration of the bielectrode ISE array. In this work, the bielectrode ISE array has been employed in the continuous flow analysis (CFA) of free copper(II) and iron(III) in seawater media. It is shown that the individual electrodes displayed Nernstian response in the metal ion buffer calibration standard over a wide dynamic range (viz., 10⁻¹⁵ to 10⁻⁵ M aCu²⁺ and 10⁻²¹ to 10⁻¹¹ M aFe³⁺), and the results of repetitive CFA analyses of free copper(II) and iron(III) in seawater are commensurate with the typical values found in coastal seawater samples. Clearly, the bielectrode ISE array may be used in the simultaneous analysis of free copper(II) and iron(III) in seawater without fear of cross-interference between the solid-state sensors.     

Voltammetric Determination of Iron(III) in Water

A square wave voltammetric procedure for the determination of trace amounts of Fe(III) was developed at an unmodified edge plane pyrolytic graphite (EPPG) electrode and a screen printed electrode (SPE). This simple procedure was applied to real samples of commercially bottled mineral water. Sensitive results in the micromolar region could be achieved without modification of the electrode. Using the WHO guideline limits for the Fe(III) concentration in drinking water, recovery percentages at an EPPG gave 103 % and 107 %, and 98.6 % and 95.0 % at a SPE for the 5.36 µM (0.3 mg L^?1) and 53.6 µM (3.0 mg L^?1) additions of Fe(III), respectively.