Samir K. Banerji

The spectrophotometric determination of uranium(VI) with methylthymol blue

Abstract Uranium(VI) and methylthymol blue form a red complex in aqueous solution with maximum development of color at pH values between 6.6 to 6.8 (λ max = 510 mμ). The net molar absorptivity is 10,625 at pH 6.7 and Beers law is obeyed in the range of 0.4–3.76 ppm of uranium. A procedure is described for the accurate spectrophotometric determination of uranium. The ratio of metal:ligand in the complex is 1:1.

The spectrophotometric determination of molybdenum and uranium with quinalizarin

Abstract Quinalizarin reacts very sensitively with molybdenum and uranium to form colored chelates having λmax at 520 and 630 nm, respectively. The molar ratio for both the chelates is 1:1 (metal:reagent). Optimum conditions including the range for adherence to Beers law, effect of pH on color intensity, effect of excess of the reagent, sensitvity, and interference of the foreign ions has been reported for the photometric determination of these metal ions using quinalizarin, in 50% ethanolic medium and at 30 °C.

Thermodynamics of some bivalent metal chelates of sodium alizarin sulphonate

Abstract The stepwise metal-ligand stability constants of alizarin red S with Ni(II), Co(II), Be(II) and UO2(II) have been determined at five different temperatures, viz. 10, 20, 30, 40 and 50°C, potentiometrically. The stepwise thermodynamic functions of these complex forming reactions like ΦG, ΔH and ΔS were also evaluated. The order of stability of bivalent metal chelates was found to be: UO2 > Be > Co > Ni.

Potentiometric studies on chelate formation of ammonium aurintricarboxylate with bivalent copper

Abstract The stepwise protonation constants of the ligand and formation constants of the chelate have been determined using the Calvin-Bjerrum technique. The log K1H and log K2H values (μ = 0·02 M) are 9·76 and 8·93 respectively at 25°C. The two copper chelates have log K1 and log K2 values of 9·33 and 3·76, respectively, at 25°C.

The spectrophotometric determination of iron(II) with methylthymol blue

Abstract The formation of complexes between iron (II) and methylthymol blue at pH 5.8 and 2.5 was studied. Complexes with the mole ratio 1:2 and 1:1 were found and respective stability constants were determined. A spectrophotometric method for determining iron (II) was devised and reported.

Spectrophotometric determination of uranium(VI) with 7-chloro-8-hydroxyquinoline-5-sulphonic acid

Abstract Uranium(VI) and 7-chloro-8-hydroxyquinoline-5-sulphonic acid form a 1:2 complex with λ max at 355 nm, in aqueous medium at pH 6.6. A procedure for accurate spectrophotometric determination of hexavalent uranium with 7-chloro-8-hydroxyquinoline-5-sulphonic acid has been described. Optimum conditions, including the effect of pH, time, temperature, order of addition of the reagents, and excess of the reagent have been studied. Range for adherance to Beers law, effective photometric range, molar absorptivity, and Sandell sensitivity have also been reported as 1–38 ppm, 5.7–28.5 ppm, 6575 and 0.036 μg of uranium/cm 2 respectively. The method has been compared with some other methods for determination of uranium spectrophotometrically, with regard to their sensitivities. Interferences of various ions in the measurement of the color have been investigated, and the tentative structure of the colored species in solution has been proposed.

Spectrophotometric study of the chelate of palladium(II) with methylthymol blue

Abstract Methylthymol blue reacts very sensitively with palladium(II) to form two complexes. The 1:1 complex has λ max at 530 nm in acidity range 0.02 to 0.05 M with respect to perchloric acid and 1:2 (metal reagent ratio) complex at 500 nm in pH range 6.8 to 7.5. Optimum conditions including the range for adherence to Beers law, effect of pH, effect of excess reagent and sensitivity are reported for the photometric determination of palladium using methylthymol blue.

A spectrophotometric determination of the stability constants of iron(III) chelates with halo substituted 8-hydroxy quinoline-7-sulfonic acid derivatives

Iron(III) forms green complexes with 5-chloro-8-hydroxy quinoline-7-sulfonic acid (CHQS), 5-bromo-8-hydroxy quinoline-7-sulfonic acid (BHQS) and 5-iodo-8-hydroxy quinoline-7-sulfonic acid (IHQS) in aqueous medium. The average values of the stability constants, log β1M, are 11·67, 12·02, and 12·22, respectively, at 25°C.

Iron(III)-5-bromo-8-hydroxyquinoline-7-sulphonate chelate — a spectrophotometric study

SummaryIron(III) forms in aqueous medium a green complex with 5-bromo-8-hydroxyquinoline-7-sulphonic acid, with maximum absorbance at 585 nm, stable in the pH range 2.5–4. The composition of the complex is 1∶1 iron∶ligand. The stability constant was found to be logK=3.48±0.05 at 25° C, and the free energy of formation was found to be = −4.8 kcal/mole at 25° C.ZusammenfassungEisen(III) bildet in wäßriger Lösung mit 5-Brom-8-hydroxychinolin-7-sulfonsäure eine grüne, zwischen pH 2,5 und 4 stabile Komplexverbindung, deren Absorptionsmaximum bei 585 nm liegt. Die Zusammensetzung entspricht dem Verhältnis Eisen∶Ligand=1∶1. Die Stabilitätskonstante entspricht bei 25° C logK=3,48±0,05, die freie Bildungsenergie bei 25° C beträgt −4,8 Kcal/Mol.

Spectrophotometric determination of iron(III) with 8-hydroxyquinoline-7-sulfonic acid

Abstract 8-Hydroxyquinoline-7-sulfonic acid has been used as a reagent for the spectro-photometric estimation of tervalant iron. The green color is developed instantaneously and is stable for about 40 hours. Absorbance has been measured at 600 mμ and pH 4. Sensitivity (Sandell) of the reagent has been found to be 0.11 μg of Fe/cm2. The interference of various ions in the measurement of the color and the probable structure of the colored species in solution have been investigated.