Study of Analytical Methods for Iron Determination in Complex Organic Liquids by Atomic Absorption Spectrometry

Abstract

In the determination of iron in complex organic liquids by atomic absorption spectrometry (A. A. S.), methods of sample preparation, such as dilution with an organic solvent and sample pretreatment to destroy organic material, are investigated. Moreover, methods of analysis using calibration curve and standard additions are presented. The possible cause of error associated with iron determination in organic samples by flame (F-A. A. S.) and graphite furnace (GF-A. A. S.) atomic absorption spectrometry are discussed.

From all of these studies, the use of graphite furnace atomic absorption spectrometry after sample dilution with methyl isobutyl ketone, and the use of the method of standard additions are advised for iron determination.     

Optimization of a simultaneous multi-element atomic absorption spectrometer

A variable-size simplex procedure was used to optimize the overall response of a simultaneous multi-element flame atomic absorption spectrometer. Seven factors (air to fuel ratio, slit width, height above the burner head, and four hollow cathode lamp currents) were optimized for copper, iron, manganese, and zinc atomic absorption. A univariate search procedure was used to determine the effect of individual factors on response. The results of the optimization showed that a comprise set of operating conditions must be used when performing multi-element determinations. The atomic absorption sensitivity of the multi-element determination as compared to single-element determination was reduced by a factor of no more than two.     

增感效应火焰原子吸收光谱法测定 铁矿石中的微量铬

提出了增感效应火焰原子吸收光谱测定铁矿石中微量铬的新方法。研究了表面活性剂十二烷基硫酸钠(SDS)对铬的增感效果。增感效应可使火焰原子吸收光谱的灵敏度提高 27倍。本法已用于测定铁矿石中的微量铬,检测限为 7.0μg/L ,回收率为 91.1%～115.9%,RSD为 4.0%。     

Comparison of a graphite tube micromethod for the determination of serum iron and total iron-binding capacity with spectrophotometric techniques

A rapid micromethod by flameless atomic absorption spectrometry is presented for the determination of total iron in serum or plasma. A clear distinction is drawn between “total iron in serum” and “serum iron”. The results for serum iron are compared with existing spectrophotometric methods. Comment is made on diurnal variation in serum iron concentration.     

流动注射-原子吸收分光光度法测定彩电荧光屏壁玻璃中钾钠钙镁铁

本文应用流动注射分析-原子吸收分光光度法(FLA-AAS)测定彩电荧光屏壁玻璃中的钾、钠、钙、镁、铁的含量、对方法中可能存在的各种影响因素、干扰情况及其消除等进行了较为详细的研究.应用所建立的方法对样品测定取得了满意结果.本文对所建立的FIA-AAS法与常规AAS法进行了比较及讨论     

Finding the 3D structure of a molecule in its IR spectrum

 The labile iron(II) and iron(III) species are complexed directly in the sample solution with 1,10 phenanthroline and ferron (8-hydroxy-7-iodoquinoline-5-sulfonic acid), respectively. The complexes thus formed are mutually adsorbed and separated by solid phase extraction. The direct determination of iron(III) and iron(II) species with flame atomic absorption spectrometry (FAAS) follows the elution of the iron(III)-ferron complex adsorbed by an anion-exchange and an iron(II)-phenanthroline complex adsorbed by a non-polar RP-18 phase. In the case of indirect determination, the iron(II)-phenanthroline complex that passes through the anion-exchange phase, is measured, and the content of iron(III) is calculated by the difference of the iron(II) and the total iron content. A direct determination with this method has been applied to the iron species analysis in wine samples and the results are compared with those obtained for the determination with adsorptive stripping voltammetry (ASV) as reference method. Received: 17 August 1995/Revised: 12 February 1996/Accepted: 14 February 1996     

Integrated scheme for micro-determination of iron oxidation states in silicates and refractory minerals

A mirco-analytical scheme incorporating four methods is described for the determination of iron(II) and iron(III) in both hydrofluoric acid-soluble and refractory minerals. The acid-soluble minerals are analyzed for FeO by direct constant-current potentiometric titration with potassium dichromate, and a separate solution is titrated similarly after Zn/Hg reduction to give total iron. The micro-determination of FeO in chromite and other refractory minerals involves dissolution in a cerium(IV)/phosphoric acid mixture and constant-current potentiometric and indirect titration of excess of cerium(IV) (phosphatocerate) with iron(II). Lithium tetraborate micro-fusion is required for measurement of total iron by atomic absorption spectrometry or spectrophotmetry. The average relative standard deviation ranged between 0.73 and 1.08%.     

Determination of total chromium in fresh water by atomic absorption spectrometry following flotation preconcentration

A flotation method is proposed for the quantitative preconcentration and determination of total chromium by electrothermal atomic absorption spectrometry in fresh water samples, without previous reduction or oxidation of the chromium ion state. Hydrated iron(III) oxide and iron(III) tetramethylenedithiocarbamate were used as precipitating collectors. The detection limit of the method is 0.01 g/L.     

Determination of aluminum in highly concentrated iron samples: Study of interferences using high-resolution continuum source atomic absorption spectrometry

High-resolution continuum source atomic absorption spectrometry (HR-CS AAS) has been used to investigate spectral and non-spectral interferences found with a conventional line source atomic absorption spectrometer in the determination of aluminum in pharmaceutical products containing elevated iron and sugar concentrations. A transversely heated graphite furnace was used as the atomizer in both spectrometers. The two most sensitive aluminum lines at 309.3 nm and 396.2 nm were investigated and it was found that an iron absorption line at 309.278 nm, in the vicinity of the aluminum line at 309.271 nm, could be responsible for some spectral interference. The simultaneous presence of iron and the organic components of the matrix were responsible for radiation scattering, causing high continuous and also structured background absorption at both wavelengths. The aluminum and iron absorption could not be separated in time, i.e., the iron interference could not be eliminated by optimizing the graphite furnace temperature program. However, an interference-free determination of aluminum was possible carrying out the measurements with HR-CS AAS at 396.152 nm after applying least squares background correction for the elimination of the structured background. Analytical working range and other figures of merit were determined and are presented for both wavelengths using peak volume registration (center pixel ± 1) and the center pixel only. Limits of detection and characteristic masses ranged from 1.1 to 2.5 pg and 13 to 43 pg, respectively. The method was used for the determination of the aluminum contamination in pharmaceutical formulations for iron deficiency treatment, which present iron concentrations from 10 to 50 g l^− 1. Spike recoveries from 89% to 105% show that the proposed method can be satisfactorily used for the quality control of these formulations.     

2-(5-羧基-1,3,4-三氮唑偶氮)-5-二乙氨基苯甲酸-过氧化氢催化动力学光度法测定痕量铁的研究

研究了铁(Ⅲ)催化H2O2氧化2-(5-羧基-1,3,4-三氮唑偶氮)-5-二乙氨基苯甲酸(CTZDBA)的褪色反应及其动力学条件,褪色反应程度与铁(Ⅲ)量在一定范围内呈线性关系,建立了测定痕量铁(Ⅲ)的催化动力学光度法。在pH4.0的HAc-NaAc缓冲溶液介质中,褪色体系的最大吸收波长581nm,Fe(Ⅲ)的质量浓度在0.0008～0.04μg/mL范围内符合线性关系,回归方程为ΔA=25.325ρ-8.02×10-3(ρ:μg/mL),相关系数为0.9977,检出限3.78×10-10g/mL,方法用于头发和面粉中痕量铁的测定,结果与AAS测定结果相符。     

Determination of Iron in Zirconium by Electrolytic Dissolution and Atomic Absorption Spectroscopy

Abstract

A simple method for the determination of iron in the range of 0.01–1.00% in zirconium metal and its alloys is described. The method is based on the electrolytic dissolution of zirconium into an organic solvent and the subsequent measurement of iron by atomic absorption spectroscopy. The method is rapid, requiring 30 minutes for one measurement.     

The determination of gold by atomic absorption spectrophotometry

Gold can be isolated from most other elements other than the platinum metals by the extraction of iron(II) 1,10-phenanthroline tetrabromoaurate in chloroform. After isolation gold can be determined in the organic solvent by atomic absorption spectroscopy or colorimetrically by decomposition of the complex and determination of the iron by bathophenanthroline.     

Simultaneous high performance liquid chromatographic determination of vanadium, nickel, iron and copper in crude petroleum oils using bis(acetylpivalylmethane)ethylenediimine as a complexing reagent

A method is described for the simultaneous high performance liquid chromatographic (HPLC) determination of copper, iron, nickel and vanadium, based on complexation of analytes by bis(acetylpivalylmethane)ethylenediimine (H(2)APM(2)en) followed by solvent extraction and HPLC separation on a reversed-phase. C-18, 5 microm column with UV detection at 260 nm. The method has been applied to the determination of metals in crude petroleum oils collected from the South Indus Basin oil fields. The results obtained are compared with those obtained by flame atomic absorption spectrometry.     

塞曼石墨炉AAS法直接测定硝酸银中的杂质

本文介绍了利用塞曼石墨炉原子吸收法直接测定硝酸银中的杂质锰、镍、铜、铁和铬。方法简单、快速、检出限低、回收率好。     

原子吸收分光光度计用于分子吸收分析测定磷的研究

应用钙元素空心阴极灯中钙元素的４２２．７ｎｍ谱线和原子吸收分光光度计，对磷钒钼黄体系进行了研究，并对生铁样品中磷的含量进行了测定，获得满意的结果。     

Determination of iron and nickel by flame atomic absorption spectrophotometry after preconcentration on Saccharomyces cerevisiae immobilized sepiolite

Iron and nickel have been preconcentrated on Saccharomyces cerevisiae immobilized sepiolite and determined by flame atomic absorption spectrophotometry (FAAS). Preconcentration studies were conducted by the column method. Effect of pH, amount of adsorbent, elution solution, flow rate and interfering ions on the recovery of the analytes have been investigated. Recoveries of Fe and Ni were 95+/-1 and 99.5+/-0.1%, respectively, at 95% confidence level. The breakthrough capacities of analytes were also investigated and found to be 0.042 mmol g(-1) for Fe and 0.055 mmol g(-1) for Ni. The proposed method was applied to the determination of iron and nickel in brass (NBS SRM 37e). The detection limit of iron and nickel were found as 0.065 and 0.087 mug ml(-1), respectively. The direct determination of trace metals by flame atomic absorption spectrometry (FAAS) is limited and difficult because of low concentration and/or matrix interferences. The proposed method is excellent for the determination of trace metal in matrixes, such as metal alloys.     

Sequential injection spectrophotometric determination of iron as Fe(II) in multi-vitamin preparations using 1,10-phenanthroline as complexing agent

A sequential injection analysis (SIA) system is proposed for the determination of iron (II). Fe(II) was determined by SIA based on the reaction between 1,10-phenanthroline and iron (II), yielding an orange–red colour complex with absorption maximum at 512 nm. The method involved aspiration of 187 μl sample/standard zone followed by a zone of a reagent solution containing 140 μl of 7.8 × 10⁻⁴ mol l⁻¹ 1,10-phenanthroline into a carrier stream to be stacked inside a holding coil and flow reversed through a reaction coil to a detector. The optimum condition was evaluated and the calibration curve is linear over a range of 0.25 to 5.0 mg l⁻¹ of Fe(II) with detection limit of 18 μg l⁻¹. A sample throughput of 40 h⁻¹ was established. This technique is found to be simple, accurate, reproducible and sensitive. The proposed method was successfully applied for the determination of total iron as Fe(II) in pharmaceutical products (multi-vitamin tablets) and is especially useful for the determination of iron (II) in tablets with lower iron (II) contents. The results were found to be in good agreement with the results obtained by manual UV/Vis spectrophotometry and flame atomic absorption spectrometry (FAAS) and with claimed values by the manufacturers.     

Catalytic kinetic spectrophotometric determination of iron with (dibromo-<Emphasis Type="Italic">p</Emphasis>-sulfonic acid arsenazo)-potassium bromate-ascorbic acid system

A new method for the determination of traces of iron was developed based on its catalytic effect on the oxidation reaction of dibromo-p-sulfonic acid-arsenazo (DBS-arsenazo, DBS-ASA) by potassium bromate in a 5.0 × 10⁻³ M sulfuric acid medium. The optimum experimental conditions for the determination of iron using iron(III)-dibromo-p-sulfonic acid-arsenazo, (DBS-ASA)-potassium bromate-ascorbic acid system and its kinetic spectrophotometric properties were studied. The absorbance difference (ΔA) is linearly related with the concentration of iron(III) over the range of 0.20–6.0 ng/mL at the maximum absorption wavelength of 520 nm and described by the equation: ΔA = 0.133c (ng/mL) — 0.0133 with a regression coefficient of 0.9966. The detection limit of the method is 0.17 ng/mL. The method has been successfully used in the determination of traces of iron in potato samples. The obtained results agree with those of atomic absorption spectrometry.     

The determination of minor amounts of tellurium in iron and steel by atomic absorption spectrophotometry

A study was made of the determination of 0.0005–0.030% tellurium in iron and steel by atomic absorption spectrophotometry. Tellurium is separated by precipitation with tin(II) chloride and concentrated by extraction of the diethyldithiocarbamate complex into amyl acetate. The procedure is free from interference by elements which are reduced by tin (II) chloride or from the diethyldithiocarbamates of these elements. The results obtained on standard samples are in agreement with those reported with X-ray spectrometry and cathode-ray polarography.     

Determination of Soluble Iron Species in Seawater Using Ferrozine

Ferrozine was used for the simultaneous determination of soluble iron(II) and iron(III) species in seawater. It was shown that iron forms complexes with dissolved organic matter in seawater, which hinders the color development of ferrozine chelates. To eliminate this factor, samples were heated and exposed to UV irradiation. The developed procedures were used for determining soluble iron species in samples of surface and silt seawater. The results agree with the data obtained by atomic absorption spectrometry.