Satendra P. Sangal

Scandium-ethylenediamine tetraacetic acid titrations

Summary Complexometric determinations of scandium with Alizarine Red S, thoron, and Murexide as chelatochromic indicators have been reported. The effect of pH on the titer value, the range of concentration, and the interferences due to foreign ions have been studied in detail.

Determination of micro amounts of uranium using 1-(o-Arsonophenylazo)-2-naphthol-3,6-disulfonate (thoron) as a colorimetric reagent

The formation of 1: 1 red color chelate ( lambda /sub max/510 m mu ) betweem uranyl ion and 1-(o-arsonophenylazo)-2-naphthol3,6-disulfonate (thoron) was used for the colorimetric determination of uranium. Measurements are possible over a wide range of temperature (up to 100 deg C) between pH 2.5 and 5.0. The system obeys Beers law from 0.63 to 34.2 ppm of uranium. The sensitivity is 0.096 v/cm/sup 2/ (Sandell) and 0.96 v/cm/sup 2/ (practical). The presence of several cations and anions interfere in the determinations. (auth)

Metal chelates of rare earths: I. Composition, stability, and analytical applications of Alizarin Red S chelates of scandium and yttrium

Abstract The formation of pink colored chelates between scandium and Alizarin Red S (λ max 500 mμ) and yttrium and Alizarin Red S (λ max 510 mμ) at pH 4.0 have been reported. Absorbance measurements indicate the composition of the chelates to be 1:2 (metal:chelating agent). Adherence to Beers law is observed over a wide range of metal concentration; the color intensities are also stable within a wide range of pH. The values of log K ( K = stability constant) have been calculated by two different methods and are (1) 9.0 and 9.4 for the scandium chelate, and (2) 9.6 and 9.5 for the yttrium chelate (pH = 4.0; temperature = 25 °C). The effect of pH, temperature, time, and diverse ions on the reactions have been studied, and suggestions have been made on the possible use of Alizarin Red S in the determination of scandium and yttrium.

Microdetermination of palladium (II) using 1-(o-arsonophenylazo)-2-naphthol-3,6-disulfonate (thoron) as a colorimetric reagent

Abstract Palladium(II) forms a reddish violet 1:1 chelate with 1-( o -arsonophenylazo)-2-naphthol-3, 6-disulfonate (thoron) ( λ max = 525 mμ). This has been used in the colorimetric determination of palladium(II) on a micro scale, and the conditions for the measurements have been worked out. Beers law is adhered to with 0.35–25.4 ppm of palladium in the presence of a large excess of thoron. Measurements may be made over a wide temperature range between pH 2.0 and 10.0. The sensitivity is 0.0106 γ/cm 2 (Sandell) and 0.106 γ/cm 2 (practical). A large number of cations and anions have been found to interfere and must be removed.

Lanthanum-Alizarine Red S chelate

Summary Formation of a pink-colored chelate between lanthanum and Alizarine Red S has been reported. The region of maximum absorbance of the chelate lies at 520 mµ . The molar ratio of lanthanum to the chelating agent has been determined to be 1:2, using three different methods: the mole ratio method, the slope ratio method, and the method of continuous variations. The chelate is stable between pH 3.5 and 6.5. The value of log k (log k = stability constant) as determined by the method of Dey et al. , the mole ratio method, and the method of continuous variations, is 8.6, 8.6, and 8.3, respectively.

Microdetermination of scandium, yttrium and lanthanum: Use of Chrome Azurol S as a chromogenic reagent

SummaryOptimum conditions for the spectrophotometric determination of scandium, yttrium and lanthanum using Chrome Azurol S as a chromogenic reagent are described. The studies include the determination of the range for adherence toBeers law, pH range of stability of the chelates, sensitivity and the influence of foreign ions.ZusammenfassungEine Arbeitsweise für die spektrophotometrische Bestimmung von So, Y und La mit Chromazurol S als Farbreagens wurde angegeben. Die Gültigkeit des Beerschen Gesetzes, die Stabilität der Chelate in Abhängigkeit vom Ph, die Empfindlichkeit der Reaktion und der Einfluß von Fremdionen wurden untersucht.

Colorimetric determination of scandium, yttrium, and lanthanum with ammonium purpurate as a chromogenic reagent

Abstract Photometric determinations of scandium, yttrium, and lanthanum with ammonium purpurate as a chromogenic reagent have been reported. The details of the determination of absorption spectra of the chelates, the effect of pH on the absorbance at λmax, the range for adherence to Beers law, and sensitivity have been worked out.

Solvent extraction and spectrophotometric determination of uranium (VI)

SummarySolvent extraction of uranium-sodium diethyldithiocarbamate with ethylmethyl ketone and separation from titanium, zirconium, thorium, lanthanum and cerium has been described. It has been found that 11.75 to 47.00 mg of uranium can be extracted from a binary mixture containing 4.78 to 19.04 mg of titanium, 9.12 to 36.48 mg of zirconium, 116.0 to 460.0 mg of thorium, 6.95 to 27.8 mg of lanthanum or 7.06 to 28.24 mg of cerium at pH 3.0. The pH range between which the separations may be carried out successfully is 2.0 to 3.5. The following cations interfere in the separations: CuII, FeIII, CoII, BiIII, NiII, CrVI, TeIV, SeIV, AgI, HgII, AsIII, SnIV, PbIV, CdII, MoVI, MnII, VV, ZnII, InIII, TlI, WVI, OsVIII and NbV.ZusammenfassungUran kann durch Extraktion als Diäthyldithiocarbamidat mit Methyläthylketon von Ti, Zr, Th, La oder Ce getrennt werden. Der günstigste pH-Bereich liegt zwischen 2,0 und 3,5. Die Trennungen wurden mit folgenden Mengen durchgeführt: U (11,75–47,00 mg); Ti (4,78 bis 19,04 mg), Zr (9,12–36,48 mg) Th (116,0–460,0 mg), La (6,95–27,8 mg), Ce (7,06–28,24 mg). Folgende Ionen verursachen Störungen: CuII, FeIII, CoII, BiIII, NiII, CrVI, TeIV, SeIV, AgI, HgII, AsIII, SnIV, PbIV, CdII, MoVI, MnII, VVI, ZnII, InIII, TlI, WVI, OsVIII sowie NbV.

p-Nitrobenzene azochromotropic acid as a chromogenic reagent for the photometric determination of scandium and yttrium

Abstract Scandium and yttrium give a pinkish violet chelate with CTB in the ratio of 1:1. Suitable conditions for the determination of the metals in micro amounts, i.e., range of adherence to Beers law, effect of pH on the stability of the chelate, effect of excess of reagent, sensitivity, and interference due to foreign ions have been worked out.

The 1:2 yttrium-thoron chelate and its application to yttrium analysis

Abstract Formation of a pink-colored chelate (λmax = 500 mμ) of yttrium with thoron has been reported at pH 4.0 and 25 °. The ratio of yttrium to thoron as determined spectrophotometrically using several methods is 1:2. The chelate is stable between pH 3.0 and 6.5. The value of log K as determined by different methods is 8.6 ± 0.3. The system adheres to Beers from 0.23 to 16.0 ppm of yttrium. The sensitivity of the system is 0.042 γ per square centimeter.