Direct and Second Order Analogue Derivative Extraction-Spectrophotometric Determination of Iron with 2 (4, 5-Dimethyl-2-Thiazolylazo)-4, 6-Dimethylphenol

Abstract

An extraction-spectrophotometric method for the determination of trace amounts of iron based on its extraction into chloroform with 2-(4, 5-dimethyl-2-thiazolylazo)-4, 6-dimethylphenol has been developed, which allows the determination of 5–28 μg Fe (?₇₇₃ = 1.38×10⁴ 1. mol^?1. cm^?1). The use of second order analogue derivative spectrophotometry allows the determination of down to 0.2–5 μg, Fe. The methods are quite selective and have been applied to the determination of iron in mineral waters.     

Amperometry with Two Polarizable Electrodes. Chelometric Determination of Rare Earths

Abstract

The method of determining rare earths by chelometric EDTA titration with biamperometric end-point indication using two stationary platinum electrodes was studied. The convenient pH range for the determination of lanthanum is 5.0 – 8.0, for yttrium 3.5 – 8.0 and for ytterbium 3.0 – 8.0. Rare earths have been determined in the presence of iron and thorium. Iron and thorium can be titrated at pH 1.5 – 2.0 and rare earths of the lanthanum group can be determined by successive titration at pH 5.0. Large amounts of rare earths of the yttrium group interfere with the determination of iron and thorium.     

The use of Chromazurol S in the presence of a mixture of cationic and non-ionic surfactants for the spectrophotometric determination of iron in cereals

Simple and sensitive methods for the spectrophotometric determination of iron(III) in food, based on the formation of coloured complexes of Fe(III) with Chromazurol S (CAS) in the presence of tetradecyltrimethylammonium bromide (TTA) or octadecyltrimethylammonium chloride (ODTA) and Triton X-100 (TX100), have been developed. Optimum pH and the concentrations of CAS, TTA, ODTA, and TX100 ensuring maximum absorbance have been determined. For the Fe-CAS-TTA-TX100 system the molar absorptivity is 1.12 × 10⁵ L/(mol cm) at 650 nm; for Fe-CAS-ODTA-TX100 it is 1.35 × 10⁵ L/(mol cm) at 659.5 nm. Beer’s law was obeyed for iron concentration in the range 0.08–0.56 μg/mL for the complex Fe-CAS-TTA-TX100 and 0.08–0.64 μg/mL for Fe-CAS-ODTA-TX100. The influence of several interfering ions has been discussed. The stoichiometry of the complexes was established by applying Job’s method. The more sensitive method, based on the Fe-CAS-ODTA-TX100 system, has been applied to the determination of iron in cereals. To evaluate the accuracy of the elaborated method, the determined content of Fe was compared to the declared value as well as to the result obtained by the reference ICP-OES method.     

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.     

Spectrophotometric Determination of Trace Amounts of Molybdenum in Steel and Pure Iron with a New Chromogenic Reagent Dimethoxyhydroxyphenylflurone

ABSTRACT

A simple method for the direct determination of trace molybdenum in low alloy steel and pure iron with selectivity and sensitivity is reported. In the presence of TritonX-100 and sulphuric-phosphoric acid medium, a new chromogenic reagent dimethoxyhydroxyphenyl-flurone (DMHPF) forms a red complex with molybdenum(VI). The molar absorptivity is obeyed from the range of 0? 8 μg/25 ml for molybdenum(VI). Most of metal ions and 35000-fold amounts of iron do not interfere with the determination of molybdenum. The proposed method has been successfully used for the determination of trace amounts of molybdenum in steel and pure iron specimens.     

A New Catalytic Reaction for the Determination of Nanomolar Concentrations of Iron(III)

Abstract

On the basis of theoretical considerations, a new catalytic reaction for the determination of nanomoler iron(III) concentrations has boon propesod, nomoly the oxidation of sulfanilic acid by potassium periodate using 1,10-phenanthroline as an activator. The optimum conditions for Fe(III) determination have been established as a result of kinetic studies.

The reaction ensures a low detection limit (2×10^?8 M), low coefficient of variation about 5% and high selectivity.     

Determination of Serum Iron and Iron Binding Capacity Using 4-(2-Pyridylazo) Resorcinol (Par)

Abstract

Procedures are described for the determination of serum iron and iron binding capacity using the chromogenic reagent 4-(2-pyridylazo) resorcinol (PAR). The high molar absorptivity of the iron (II) PAR complex makes possible an approximate two fold increase in sensitivity over previous methods. The described procedures have few interferences, and give linear results for samples containing 0 – 750 μg/dl of iron.     

Quantitative Determination of Iron and Aluminium in Some Alloys and Silicate Rocks After a Cation Exchange Separation on Zirconium(IV) Phospho and Silico Arsenates

Abstract

A rapid and quantitative method has been developed for the analysis of some iron and aluminium based alloys and silicate rocks using zirconium(IV) based arsenophosphate and arsenosilicate cation exchangers. The method is simple, reproducible and precise with a standard deviation <3%, for the direct determination of iron and aluminium in rocks and alloys. The low standard deviation values suggest that the method should be useful for the standardization purposes.     

A Fluorescence Quenching Method for the Determination of Chromium(VI) with L-Tyrosine

Abstract

A fluorescence quenching method for the determination of Cr(VI) in aqueous solution is described. The fluorescence intensity of the system is linear ever the range 5×10^?6 - 1.0×10^?4 M Cr(VI). The method has been applied to the determination of Cr(VI) In cast iron and waste water.     

Detection and Spectrophotometric Determination of Pyruvic Acid

Abstract

A colour reaction has been studied for the identification and the spectrophotometric determination of pyruvic acid with iron(III) nitrate. The detection limit was 50 μg. Beer's law is obeyed in the concentration range 0.01 to 0.20 m mole of pyruvic acid.     

Spectrophotometry Determination of Ciprofloxacin in Serum Using Iron(III) Ion as Chromogenic Agent

ABSTRACT

An analytical procedure for the determination of ciprofloxacin in serum without previous extraction has been developed. The determination was carried out using iron(III) nitrate as chromogenic agent, with the addition of sodium dodecylsulfate, at pH = 3.0. Absorbance was measured at 430 nm. The range of linearity was between 0.5 – 20.0 μg/mL with a detection limit 0.2 μg/mL.     

Phase-Sensitive A. C. Polapography of 1, 10-Phemanthroline Determination of Trace Concentrations of Iron

Abstract

Indirect determination of trace concentrations of iron was studied by monitoring the decrease of the a. c. polarographic wave of 1, 10- phenan tli rol i ne (phen). Fundamental harmonic, with current measured at Φ = 90°, was utilized. The best supporting electrolyte was found to be a 0.6 H NaClO₄ solution of pH 4.5 with acetate buffer. The approach consists in running polarograns for the supporting electrolyte containing buffer and phen, subsequent to sample addition, and after each addition of standard, respectively. The effect of pH, buffer system, some common anions and iron(III) was investigated. The method has been applied to the determination of iron in pure samples, reference standard material, and tap water. The detection limit was 4 ng mL^?1.     

Analysis of Fruit Juices by Inductively Coupled Plasma-Maas Spectroscopy: Determination of Iron,Tin and Lead by Direct Aspiration

Abstract

A method has been developed for the determination of iron, tin and lead in fruit juices using inductively coupled plasma mass spectroscopy. These metals can be determined by direct aspiration of the sample after suitable dilution with water. It is not necessary to treat the sample prior to analysis.     

Determination of iron and titanium in kaolins by the method of non-dispersive X-ray fluorescence

The possibility of application of the radioactive source excited X-ray fluorescence analysis for titanium and iron determination in kaolins to the routine test of the refinement process has been studied. The iron content can be determined with a simple counting system using a single-channel pulse height analyser, argon filled proportional counter and¹⁰⁹Cd source of 3 mCi for the excitation of K Fe rays. The samples were analysed both as pellets and powders. The iron content ranged from 0.2–2.5% and titanium from 0.1–0.64%. For simultaneous determination of titanium and iron a Si(Li) spectrometer has been used. The²³⁸Pu source has been used for K Fe and K Ti excitation. It is the most convenient source for simultaneous determination of titanium and iron.⁵⁵Fe is the most efficient source for the determination of titanium alone. The best values of precision and determination limit have been achieved for iron with²³⁸Pu and for titanium with⁵⁵Fe.     

Complex Formation Equilibria of Iron(III) With 2-Hydroxy-3- Pyridinol and 2-Mercapto-3-Pyridinol. Spectrophotometry Determination of Iron(III) In Multivitamins

ABSTRACT

The complex equilibria of iron(III) with 2-hydroxy-3-pyridinol (HHP), and 2-mercapto-3-pyridinol (MHP) were studied spectrophotometrically in 40% (v/v) ethanol and an ionic strength of 0.1M (NaCIO₄). The complexation reactions were demonstrated and characterized using graphical logarithmic analysis of the absorbance pH-graphs. After considering all the different parameters a simple, rapid, sensitive and selective method for spectrophotometric determination of trace levels of iron(III) was proposed based on the formation of (Fe -MHP) complex at pH 2.5 (λ_max = 640 nm, ? = l×10⁴ L mol^?1 cm^?). The interference of a large number of foreign ions was investigated. The method has been applied successfully for the determination of iron content in some multivitamins with mineral preparations and infant milk products.     

Photochemical Titration of Imine Chelons

Abstract

A photochemical titration for determination of the analytically useful imine chelons 1,10-phenanthroline and 2,4,6-tripyridyl-s-triazine has been developed. The titrant, iron(II), is photolytically generated from iron(III)-citrate; citrate buffers the solution permitting rapid reaction of iron(II) with the chelons. A single mercury vapor arc serves as source for both photolysis and the photometric end point (546 nm); 1 to 40 micromoles of chelon can be titrated with RSDs less than 1%. 2–2′ bipyridine cannot be titrated by continuous photolysis due to a slow complex formation step.     

Direct Multielement Determination of Selected Elements in Rat Urine by Inductively Coupled Plasma Atomic Emission Spectroscopy

Abstract

A method has been developed for the direct determination of dissolved elements in samples of rat urine of less than 2 ml, by Inductively Coupled Plasma Atomic Emission Spectroscopy. The method is capable of measuring copper, iron, magnesium, manganese, phosphorus and zinc.     

Determination of Micro Amounts of Metallic Silver in Silver Salt Matrices

ABSTRACT

A spectrochemical method has been developed for the quantitative determination of metallic silver in silver nitrate and silver chloride or bromide matrices exposed to light. The method is based on the oxidation of silver(0) by iron(III) at pH 3.5 in the presence of ferrozine. The resulting absorbance of the iron ferrozine complex is measured at 562 nm. Less than 0.1 mg of metallic silver can be determined with a relative standard deviation better than 6%.     

Spectrophotometric Determination of Iron with EDDHA (Ethylenediamine N N′ Bis O-Hydroxyphenilacetic Acid) by Derivative Spectroscopy

Abstract

Derivative spectrometry is applied to a spectrophotometric determination of iron with EDDHA. the effect of amount of reagent, acidity, time and temperature have also been studied. the interval of application of the method is increased to 0.16–15.36 μg Fe(III) mL^?1. the reproducibility, precision and potential interferents have been investigated. the interferences due to chlorate, wolframate, molybdate, permanganate, cyanide, cromate, Cu(II), Be(II), Ce(III), Al(III), Hg(II), Sn(II) and Zn(II) are reduced in this new procedure.     

Coprecipitative Preconcentration and Differential Pulse Cathodic Stripping Voltammetric Determination of Selenium (IV)

Abstract

A DPCSV procedure for the determination of selenium (IV) with a prior preconcentrative coprecipitation on iron (III) hydroxide has been developed. The experimental conditions for coprecipitation of selenium (IV) onto iron (III) hydroxide, viz. pH, iron (III) concentration, volume of aqueous phase and selenium concentration, were optimized. The coprecipitated selenium (IV) is dissolved in 10 ml of 0.1 M HCl and analysed using DPCSV in the presence of copper (II). Selenium concentrations as low as 10–100 ng present in 500 ml of the aqueous phase could be determined. The method is precise and has been applied to the analysis of sea water and reference material samples.