Determination Of Manganese In Steel Research Articles

Precise determination of manganese in steel by dc glow discharge optical emission spectrometry associated with voltage modulation technique

A voltage modulation technique was applied for the precise and accurate determination of manganese in steels in dc glow discharge optical emission spectrometry. Emission signals from the glow discharge plasma are modulated by a cyclic variation of the discharge voltage so that only the desired signals can be detected at very low noise levels by using a lock-in amplifier. Mn determination in low-alloyed steels was performed to estimate the repeatability of the analytical result. For each measurement, the relative standard deviation (R.S.D.) of the intensities of the Mn I 403.08-nm line was ca 0.1% when a steel sample containing 0.329 mass% Mn was employed. Averaging all analytical values, which are obtained in various discharge conditions, yields statistical information on the precision and accuracy of the analytical values obtained. The relative error from the recommended value is calculated to be 0.5%. The R.S.D. over the analytical values is 1.5%, representing the overall analytical performance of this technique.

Development of a new flow-through bulk optode for the determination of manganese(III).

A flow-through bulk optode based on the use of 1-(2-pyridylazo)-2-naphthol (PAN) immobilized in a plasticized poly(vinyl chloride) membrane entrapped in a cellulose support, in conjuntion with the flow injection analysis technique, is proposed for the determination of manganese(II). The calibration graph obtained at 570 nm was linear in the range 0.27-27.5 mg L(-1) (5 x 10(-6)-5 x 10(-4) M) Mn(II) with a detection limit of 0.18 mg L(-1). The coefficients of variation of the sensor response for 5.5 mg L(-1) of Mn(II) were +/-0.22% for consecutive measurements (n = 10), +/-0.48% between days (n = 5) and +/-0.38% between different membranes (n = 6). The sensor was readily regenerated with the carrier acetic acid/acetate buffer of pH 4.5. The method was applied to the determination of manganese in steels, waters and lemon tree leaves.

Determination of manganese in steel after extraction of dimethyldistearylammonium permanganate

Manganese(VII) can be determined spectrophotometricaly at 546 nm after extraction as dimethyldistearylammonium permanganate into dichloromethane. The effect of pH, reagent concentration, conditions and diverse ions are reported. The calibration graph is linear up to 110 μg Mn. The apparent molar absorptivity is 2.3 × 10 3 l mol −1 cm −1. The relative standard deviation is 0.3% ( n = 10) for 100 μg of Mn. The system has been applied to a range of steels.

Uncertainty of measurement in spectrophotometric analysis: A case study

Chemical analysis has gained in importance in recent years because of an increase in international trade. Hence the quality of the results of chemical analysis and the extent of their reliability for the purpose for which they are used has become extremely important. This requirement is fulfilled by indicating the uncertainty of the measurement, which gives a measure of the confidence that can be placed on the result irrespective of the method used. In this paper, we evaluate the uncertainty of measurement for the determination of manganese in steel by spectrophotometry, following the internationally accepted guidelines brought out by ISO. Standard steel no. 20.02, obtained from NML, Jamshedpur, India, has been taken as the unknown sample and the concentration of manganese in it has been measured against certified reference steel BCS No. 232 (UK). The percentage of Mn in the NML steel sample is estimated as (0.56 ± 0.03) %m/m. The reported expanded uncertainty of the measurement is stated as the standard uncertainty of measurement multiplied by a coverage factor of 2, which for a normal distribution corresponds to a coverage probability of approximately 95%.

Spectrophotometric Determination of Manganese in Steels by On-Line Electrochemical Oxidation

The aim of this work is to propose a flow spectrophotometric procedure for manganese determination in steel based on electrochemical oxidation of Mn(II) to Mn(VII) at a Pt electrode surface by means of the catalytic effect of Ag(I). The on-line oxidation step was obtained by injecting sample and electrolyte solution directly into an electrolytic cell. After electrolysis, the injectate was homogenized by bubbling air. The permanganate ions produced were passed through the spectrophotometer where absorbance was monitored at 545 nm. Effects of direct current, silver concentration, timing, flow rates, concentration and composition of support electrolyte were investigated. Direct current and silver content manifested themselves as the most relevant parameters. For determination of manganese in the 5.00 - 150 mg L-1 range (r = 0,9998) and 60 s electrolysis time, the sample throughput was 20 h-1. Accuracy was assessed by analyzing ten steel standard reference materials. Results are precise (R.S.D. < 3%) and in agreement with certified values of reference materials and with standard methods at 95% confidence level.

Flow-injection extraction-spectrophotometric determination of manganese(VII) with benzyltributylammonium cations

A flow-injection manifold has been developed for the spectrophotometric determination of manganese(VII) at 548 nm after extraction into chloroform of the ion-associate, benzyltributylammonium permanganate. The carrier stream was a pH 6 buffer containing 10% (w/v) ammonium fluoride and the reagent stream was 0.10% (w/v) benzyltributylammonium chloride. The injection rate was 20 h −1. The calibration graph is linear up to 25 μg ml −1 and the detection limit (3 × baseline noise) is 0.91 μg ml −1 Mn(VII), based on 250-μl injection volumes. The system has been aplied to the determination of manganese in steels and a cupro-nickel alloy.

Rapid and selective spectrophotometric determination of manganese in steels and alloys using resacetophenone oxime

A sensitive spectrophotometric method is developed for the determination of manganese in aqueous medium. The metal ion forms a yellowish brown coloured complex with resacetophenone oxime (RPO) in ammonium chloride and ammonium hydroxide buffer of pH 10.5. The 1:1 complex shows maximum absorbance at 380 nm with a Beer's law range of 0.09–1.7 ppm. The molar absorptivity and the Sandell sensitivity are found as 2.5 × 10 4 l.mole −1.cm −1 and 0.002 μg/cm 2, respectively. The stability constant of the complex calculated by Job's method is 7.5 × 10 5. The interfering effects of various cations and anions are studied. The present method is applied to the determination of manganese in some steel and alloy samples.

Kinetic spectrophotometric study of the reaction between terephthalmonohydroxamic acid and manganese(II). Determination of manganese in steels

The working conditions affecting the kinetics of formation of the complex between terephthalmonohydroxamic acid and manganese were studied and optimized and both classical kinetic determination methods and two new methods based on semi-logarithmic fittings of the non-linear portions of absorbance-time curves and on theoretical equations describing the kinetics of the process were used for the determination of microgram amounts of manganese. The kinetic methods thus developed and the new equilibrium spectrophotometric method were applied to the determination of manganese in steels.

Spectrophotometric determination of manganese in steels after extraction of permanganate with benzyltributylammonium chloride

Manganese(VII) (0–100 μg) can be determined spectrophotometrically at 548 nm after its extraction as benzyltributlammonium permanganate, at pH 6, into chloroform. The effects of pH, reagent concentrations and diverse ions are reported. The system has been applied to the determination of manganese in a variety of steels. For the determination of 60 μg of manganese the relative standard deviation was 0.19% (7 measurements).

Flow-injection extraction-spectrophotometric determination of permanganate with the triphenylsulphonium cation

Permanganate can be determined spectrophotometrically at 548 nm after flow-injection extraction into chloroform of the ion-associate triphenylsulphonium permanganate. The carrier stream was a pH 6 buffer containing 10% (w/v) ammonium fluoride and the reagent stream was 0.10% (w/v) triphenylsulphonium chloride. The injection rate was 20 h−1. The calibration graph is linear up to 40 μg ml−1 and the detection limit is 1.10 μg ml−1 Mn(VII), based on injection volumes of 250 μl. The system has been applied to the determination of manganese in steels and a cupro-nickel alloy.

Extraction and Spectrophotometric Determination of Manganese(VII) with N1-Hydroxy-N1,N2-Diphenylbenzamidine

Abstract Spectrophotometric determination of manganese(VII) at 614 nm after its extraction with N1 -hydroxy-N1,N2-diphenylbenzamidine into amyl alcohol at pH 7–8 is described. Beer's law was obeyed for 0.1–10 μg ml−1 Mn(VII). The effects of experimental variables and of several diverse ions on the determination of manganese(VII) have been studied. The method has been applied to the determination of manganese in steels and in water extracts of a commercial tea and is found to be simple, precise and highly selective.

Extraction-spectrophotometric determination of manganese with 5,5′-dithiodisalicylhydroxamic acid (DTDSHA)

The spectrophotometric characteristics of the red-violet complex formed between manganese and 5,5′-dithiodisalicylhydroxamic acid after extraction into bencenic solution of trioctylmethylammonium chloride (Adogen 464) were studied. The extract shows an absorption maximum at 495 nm and the extraction is complete at pH >9. The stoichiometry of the complex at pH 10 is 3:2 (reagent:manganese) and 1:6 for the ionic association complex (3:2):trioctylmethylammonium ion. For a V w V o ratio of 10 the system follows Beer's law (pH 10; λ = 495 nm) over the concentration range 0.3–2.3 ppm (ϵ = 1.96 × 10 3 liter · mol −1 · cm −1 for the organic phase). A new method for the extraction-spectrophotometric determination of manganese is proposed. This method is applied for determination of manganese in steel.

The determination of manganese in steels using proton-induced prompt photon emission

Prompt gamma-rays of 126, 412, 477, 931 and 1316 keV from the bombardment of manganese with 4.0 and 4.5 MeV protons were used to determine manganese in steels. The method was suitable for Mn concentrations above 100 μg · g −1. Bombarding currents depended on the gross gamma-ray yield from the target and varied between 0.5 and 3.0 nA. The duration of analysis depended on the Mn content and the precision required, but did not exceed 20 min. The relative precision was 2.5%.

Coherent forward scattering spectrometry of manganese and chromium using a xenon lamp and a tellurous oxide acousto-optic tunable filter

Coherent forward scattering spectrometry has capabilities of simultaneous multielement analysis and simple instrumentation. Considering these features the authors used a xenon lamp as a continuous excitation light source and a tellurous oxide acousto-optic tunable filter as a scanning monochromator. This simple system was applied to the simultaneous determination of manganese and chromium. An analytical procedure for the determination of manganese in steels was developed and applied to standard reference materials. It was further shown that the dynamic range for both elements can be apparently extended by the use of various exciting lines and combinations of hollow cathode lamps, the xenon lamp, the tunable filter and a spectrometer.

Removal of graphite by oxidation with perchloric acid plus periodic acid: Inapplicability to the spectrophotometric determination of manganese in steel

An attempt has been made to improve the Willard and Greathouse periodate method for the determination of manganese in high-carbon steel and cast iron by oxidizing the graphite with periodic acid in the presence of perchloric acid and phosphoric acid. Graphite is rapidly oxidized at 150° by this mixture but manganese is lost by volatilization as the heptoxide and decomposition of the latter on hot surfaces to manganese dioxide. No way was found for either the quantitative removal and recovery of manganese by volatilization or for quantitative return to the main solution. The spectrophotometric determination of manganese in the supernatant liquid after allowing graphite to settle yields imprecise but not wholly unacceptable results; for the highest accuracy, graphite should be removed along with silica following dehydration of the latter with perchloric acid.

Ammonium hexanitratocerate(iv) as an oxidising agent—III : Photometric determination of manganese II through oxidation to manganese VII

Manganese II is oxidised to permanganic acid by treatment with a slight excess of ammonium hexanitratocerate(IV) in a 0.5–2 M nitric acid medium at room temperature. The reaction is markedly catalysed by silver nitrate, so that quantitative oxidation is possible within l min. Conditions have been developed for utilising the catalysed reaction for the colorimetric determination of manganese over the range 0.33–19.93 mg/litre. The new method has the advantage over those currently available in that the oxidation to manganese VII is stoichiometric at room temperature. Under the conditions prescribed the permanganic acid formed is stable for at least 24 hr. Interference from sulphate and from chloride, bromide and iodide can be eliminated by treating the test solution with barium nitrate or silver nitrate, respectively, before the oxidation with cerium IV. Application of the method to the determination of manganese in steel is considered.

Spectrophotometric determination of manganese II with benzohydroxamic acid

Manganese II reacts with benzohydroxamic acid in ammoniacal solution to form a stable reddish-brown complex (λ max 500 mμ). The reagent does not absorb at this wavelength and the concentration of ammonium hydroxide is not critical above pH 10. The sensitivity is 0.015 μg of manganese per cm 2 for log I 0/I = 0.001 ; the spot-plate sensitivity is 0.2 μg of manganese per 0.05 ml. Beer's law is obeyed up to a manganese concentration of 10 ppm in 1-cm absorption cells. The colour reaction takes place in non-aqueous solvents; optimum conditions for the reaction in dimethylformamide have been established. Interference by iron, cobalt and copper is avoided by the separation of manganese from these ions by ion-exchange. Development of the method included a study of the effect of temperature, pH, reagent: manganese ratio, stability of the complex and the rate of colour formation. The spectrophotometric method has been successfully applied to the determination of manganese in steel, bronze and magnesium alloy.

Spectrophotometric determination of manganese in steel

Spectrophotometric determination of manganese in steel

Determination of manganese in steel and iron by the persulphate-arsenite method

Determination of manganese in steel and iron by the persulphate-arsenite method

Determination of manganese in steel by the Proctor-Smith reaction in presence of phosphoric acid

Determination of manganese in steel by the Proctor-Smith reaction in presence of phosphoric acid