T. Sreenivasulu Reddy

Analytical properties of 1-phenyl-1,2-propanedione-2-oxime thiosemicarbazone: simultaneous spectrophotometric determination of copper(II) and nickel(II) in edible oils and seeds

The analytical properties of 1-phenyl-1,2-propanedione-2-oxime thiosemi-carbazone (PPDOT) are described for the first time. The reagent gives colour reactions with copper(II) and nickel(II) in sodium acetate-acetic acid buffer medium. The copper complex shows maximum absorbance at 465 nm while the nickel complex at 395 nm. Therefore, these colour reactions have been advantageously used for the simultaneous spectrophotometric determination of copper(II) and nickel(II) in synthetic mixture and also in edible oils and seeds.

Extraction and simultaneous spectrophotometric determination of vanadium(IV) and vanadium(V) in admixture with 2-hydroxyacetophenone oxime

Vanadium(IV) and vanadium(V) in the presence of 2-hydroxyacetophenone oxime were extracted quantitatively into chloroform in the pH ranges 3.6–4.5 and 2.7–4.1, respectively. The organic layer showed absorbance maxima at 345 and 350 nm for VIV and VV, respectively. Studies of the behaviour of VIV were also carried out at a wavelength of 350 nm. Vanadium(V) absorbed considerably beyond 380 nm whereas VIV had negligible absorbance in this region. The absorbance of the organic layer, for both VIV and VV, was unaltered, even after 4 d. The composition of the complexes formed was established to be 1 : 2 (metal : ligand) by Jobs method. Interference studies were carried out for both VIV and VV and methods are suggested for eliminating interference by foreign ions. Both VIV and VV are extracted quantitatively at pH 4; this extraction was exploited successfully for the simultaneous determination of VIV in the range 1–3 µg ml–1 and VV in the range 1–6 µg ml–1 by measuring the absorbances at 350 and 400 nm, respectively.

Rapid, selective, direct and derivative spectrophotometric determination of titanium with 2,4-dihydroxybenzaldehyde isonicotinoyl hydrazone.

A simple and sensitive spectrophotometric method is developed for the determination of titanium in aqueous medium. The metal ion forms a reddish brown coloured complex with 2,4-dihydroxybenzaldehyde isonicotinoyl hydrazone (2,4-DHBINH) in the pH range 1-7. The complex shows two absorption maxima, one at 430 nm and the other at 500 nm. The reagent shows appreciable absorbance of 430 nm and negligible absorbance at 500 nm at pH 1.5. Beers law is obeyed in the range 0.09 to 2.15 mug ml(-1) of titanium(IV). The molar absorptivity and the Sandells sensitivity of the method are 1.35 x 10(4) 1 mol(-1) cm(-1) and 0.0049 mug cm(-2), respectively. A method for the determination of titanium by first-order derivative spectrophotometry is also proposed. The methods have been employed successfully for the determination of titanium in several alloy and steel samples.

o-Hydroxyacetophenone thiosemicarbazone as a reagent for the rapid spectrophotometric determination of palladium

o-Hydroxyacetophenone thiosemicarbazone has been synthesized and employed as a new reagent for the spectrophotometric determination of palladium(II), which forms two complex species with it in aqueous dimethylformamide at pH 6.0, these having 1:1 and 1:2 metal-ligand ratios. The Job and molar-ratio plots have an unusual shape that is due to the stepwise conversion of the 1:1 complex into the 1:2 species. The molar absorptivity at 370 nm is 9 x 10(3) l.mole(-1).cm(-1). Beers law is obeyed over the range 0.42-10.6 mug/ml palladium.

Direct and Derivative Spectrophotometric Determination of Copper(II) with 5-Bromosalicylaldehyde Thiosemicarbazone

A rapid and sensitive spectrophotometric method is developed for the determination of Copper (II) in aqueous DMF medium. The metal ion forms a light greenish yellow coloured complex with 5-bromo salicylaldehyde thiosemicar- bazone (5-BSAT) in acidic medium. The complex shows absorption maximum at 390nm. Beers law is obeyed in the range 0.31 - 6.35 � gml -1 of Copper (II). The molar absorptivity (� ) and Sandells sensitivity are found to be 1.08 X 10 4 l mole -1 cm -1 and 0.062 � gcm -2 respectively. A method for the determination of copper by third derivative spectrophotome- try is also proposed. The methods have been employed successfully for the determination of copper in grape leaves and aluminum based alloy samples.

First Order Derivative Spectrophotometric Determination of Vanadium(V) and Iron(III) Individually and Simultaneously

A novel, sensitive and highly selective first derivative spectrophotometric method is proposed for the determination of vanadium(V) and iron(III) metal ions separately and simultaneously in a mixture. 2-Hydroxy-1-naphthaldehyde benzoylhydrazone (OHNABH) reacts with vanadium(V) and iron(III) in sodium acetate–acetic acid buffer medium (pH 5.0) forming yellow and yellowish brown colored soluble complexes, respectively. The first derivative curves of these colored solutions show maximum derivative amplitudes at 465 nm (V(V)) and 540 nm (Fe(III)) obeying Beers law in the range 0.12–2.50 μg ml–1 and 0.14–4.20 μg ml–1, respectively. Large number of foreign ions do not interfere in the present method. A very simple and accurate simultaneous first derivative method is also reported for the determination of V(V) and Fe(III) in mixtures without solving simultaneous equations. The method is applied for the analysis of various natural samples, food and biological materials.

Extraction and spectrophotometric determination of nickel with 2-hydroxyacetophenone oxime and simultaneous determination of copper and nickel.

It is observed that 2-hydroxyacetophenone oxime can be used for the quantitative extraction of nickel in the pH range 6.6-7.8 into methyl isobutyl ketone. The organic layer shows maximum absorbance at 375 nm. Beers law is obeyed over the range 1-6 ppm. The colour of the organic layer is stable for more than 48 hr. Interferences have been studied and methods are suggested for their elimination. Copper and nickel are both quantitatively extracted at pH 7 and can be determined simultaneously and accurately in the range 1-6 microg/ml for copper and 1-4 microg/ml for nickel.

Erratum to: Direct and derivative spectrophotometric determination of thorium with 2,4-dihydroxybenzaldehyde isonicotinoyl hydrazone

A simple and sensitive spectrophotometric method is developed for the determination of throium in aqueous medium. The metal ion forms yellow coloured complex with 2,4-dihydroxybenzaldehyde isonicotinoyl hydrazone (2,4-DHBINH) in the pH range 2.0–8.0. The complex shows an absorption maximum at 390 nm. The absorbance of the complex is maximum at pH 5.5 Beers law is obeyed in the range 0.30–7.00 μg/ml of thorium(IV). The molar absorptivity and the Sandells sensitivity of the method are 2.20· 104 l·mol−1·cm−1 and 0.0106 μg/cm−2, respectively. The interference of various ions was studied. The composition of the complex is 1:1 {Th(IV) : 2,4-DHBINH}. The first derivative spectrum of the complex shows a zero cross at 391.2 nm and maximum amplitude at 415 nm. Thus a sensitive derivative spectrophotometric method for the determination of Th(IV) is proposed.