Kinetic spectrophotometric method for the determination of selenium(IV) by its catalytic effect on the reduction of spadns by sulphide in micellar media

Keyvanfard, Mohsen; Sharifian, Atefeh

doi:10.1134/s1061934806060153

Cited by 15 publications

(12 citation statements)

References 15 publications

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“…The proposed method has the advantages of low cost, simple operation, a linear range of 35 fold, reproducibility, accuracy and, most importantly, low DLs, comparable with the DLs obtained by the existing catalytic kinetic techniques. [23][24][25][26][27][28][29][30][31][32][33][34][35][36] As a result, the proposed kinetic method can be simply replaced by the use of common chromatographic and atomics spectroscopic method with speedy analysis in order to determine and speciate inorganic Se and Se species in a simple matrix such as environmental surface waters. In addition, kinetic methods available, especially for use in underdeveloped and developing countries in order to detect the selenium present in real life samples can routinely be utilized for a local laboratory.…”

Section: Discussionmentioning

confidence: 99%

The Investigation of a Novel Indicator System for Trace Determination and Speciation of Selenium in Natural Water Samples by Kinetic Spectrophotometric Detection

Gürkan¹,

Ulusoy²

2010

Bulletin of the Korean Chemical Society

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A novel catalytic kinetic method is proposed for the determination of Se(IV), Se(VI) and total inorganic selenium in water based on the catalytic effect of Se(IV) on the reduction of bromate by p-nitrophenylhydrazine at pH 3.0. The generated bromine, Br2 or Cl2 plus Br2 in 0.1 M NaCl (or NaBr) environment efficiently decolorized Calmagite and the reaction was monitored spectrophotometrically at 523 nm as a function of time. In this indicator reaction, bromide acted as an activator for the catalysis of selenium (IV) and a reducing agent for selenium (VI) at pH 3.0, which allowed the determination of total selenium. The fixed time method was adopted for the determination and speciation of inorganic selenium. Under the optimum conditions, the calibration graph are linear in the range 1 -35 µg L for the fixed time method (7 min). All of the variables that affect the sensitivity at 523 nm were investigated, and the optimum conditions were established. The interference effect of various cations and anions on the Se (IV) determination was also studied. The selectivity of the selenium determination was greatly improved with the use of the strongly cation exchange resin such as Amberlite IR120 plus. The proposed kinetic method was validated statistically and through recovery studies in natural water samples. The RSDs for ten replicate measurements of 5, 15 and 25 µg L -1of Se(IV) and Se(VI) was changed between 2.1 -4.85%. Analyses of a certified standard reference material (NIST SRM 1643e) for selenium using the fixed-time method showed that the proposed kinetic method has good accuracy. Se(IV), Se(VI) and total inorganic selenium in environmental water samples have been successfully determined by this method after selective reduction of Se(VI) to Se(IV).

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Section: Discussionmentioning

confidence: 99%

The Investigation of a Novel Indicator System for Trace Determination and Speciation of Selenium in Natural Water Samples by Kinetic Spectrophotometric Detection

Gürkan¹,

Ulusoy²

2010

Bulletin of the Korean Chemical Society

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“…Therefore, the optimum bromate concentration of 0.05 M was selected. In many reactions, suitable micelles can affect the rate of reaction [21][22][23][24][25][26][27][28]. A micelle usually can be formed by the aggregation of charged organic molecules.…”

Section: Effect Of Chemical Variablesmentioning

confidence: 99%

Flow-injection spectrophotometric determination of vanadium with malachite green oxalate by bromate in acidic and micellar medium

Keyvanfard

Abedi

2011

Rare Metals

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A flow injection method is proposed for determining vanadium(V). The method is based on its catalytic effect on the oxidation of malachite green oxalate by bromate. The reaction was monitored spectrophotometrically by measuring malachite green oxalate absorbance at λ max = 625 nm. The reagents and manifold variables, which have influences on the sensitivity, were investigated and the optimum conditions were established. The optimized conditions made it possible to determine vanadium in the ranges of 10-140 ng/mL with a detection limit of 5.2 ng/mL and a sample rate of 20 ± 5 samples/h.

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“…This is not only because of its relatively high first ionization potential leading to lower ionization efficiency in the plasma, but also because of the severe interferences of 40 Ar 36 Ar, 40 Ar 38 Ar, and 40 Ar 40 Ar to the major isotopes of 76 Se (natural abundance 9.37%), 78 Se (23.77%), and 80 Se (49.61%), respectively. 40 Ar 37 Cl and 81 Br 1 H polyatomic spectral interferences to 77 Se (7.63%) and 82 Se (8.73%) also make the determination of Se very difficult when a sample contains even traces of chloride or bromide. Atomic fluorescence spectrometry (AFS) is a well-established and sensitive alternative detection technique for Se speciation [8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 98%

“…Some of these methods have high limit of detection, or suffer from many interfering ions such as Te(IV) and As(III), or have time-consuming procedures, or these reagents used are unstable. Additionally, few catalytic kinetic methods for the determination of Se(IV) in water systems have been reported in the literature [33][34][35][36][37][38][39][40], but only two of the recently published catalytic kinetic methods [41][42] allow the determination of Se(IV), Se(VI), and total inorganic Se in water samples. Therefore, there is still a need to develop the more sensitive and selective catalytic kinetic spectrophotometric method for the determination and speciation of selenium in real samples.…”

Section: Introductionmentioning

confidence: 99%

A novel indicator system for catalytic spectrophotometric determination and speciation of inorganic selenium species (Se(IV), Se(VI)) at trace levels in natural lake and river water samples

et al. 2011

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A novel catalytic kinetic method is proposed for the determination of Se(IV), Se(VI), and total inorganic selenium in water based on the catalytic effect of Se(IV) on the reduction of Celestine blue by sodium sulfide at pH 7.0 phosphate buffer. The fixed-time method was adopted for the determination and speciation of inorganic selenium. Under the optimum conditions, the two calibration graphs are linear with a good correlation coefficient in the range 2-20 and 20-200 μg⋅L −1 of Se(IV) for the fixed-time method at 30°C. The experimental and theoretical detection limits of the developed kinetic method were found to be 0.21 and 2.50 μg⋅L −1 for the fixed-time method (3 min). All of the variables that affect the sensitivity at 645 nm were investigated, and the optimum conditions were established. The interference effect of various cations and anions on the Se(IV) determination was also studied. The selectivity of the selenium determination was greatly improved with the use of the strongly cation exchange resin such as Amberlite IR120 plus as long as chelating agents of thiourea and thiosulphate. The proposed kinetic method was validated statistically and through recovery studies in natural water samples. The relative standard deviations (RSDs) for ten replicate measurements of 2, 10, and 20 μg⋅L −1 of Se(IV) change between 0.35% and 5.58%, while the RSDs for ten replicate measurements of 3, 6, and 12 μg⋅L −1 of Se(VI) change between 0.49% and 1.61%. Analyses of a certified standard reference material (NIST SRM 1643e) for selenium using the fixed-time method showed that the proposed kinetic method has good accuracy. The Se(IV), Se(VI), and total inorganic selenium in lake and river water samples have been successfully determined by this method after selective reduction of Se(VI) to Se(IV).

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Kinetic spectrophotometric method for the determination of selenium(IV) by its catalytic effect on the reduction of spadns by sulphide in micellar media

Cited by 15 publications

References 15 publications

The Investigation of a Novel Indicator System for Trace Determination and Speciation of Selenium in Natural Water Samples by Kinetic Spectrophotometric Detection

The Investigation of a Novel Indicator System for Trace Determination and Speciation of Selenium in Natural Water Samples by Kinetic Spectrophotometric Detection

Flow-injection spectrophotometric determination of vanadium with malachite green oxalate by bromate in acidic and micellar medium

A novel indicator system for catalytic spectrophotometric determination and speciation of inorganic selenium species (Se(IV), Se(VI)) at trace levels in natural lake and river water samples

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