Extraction-spectrophotometric determination of iron as the ternary tris(1,10-phenanthroline)-iron(II)-picrate complex

A highly sensitive extraction-spectrophotometric method has been developed for the determination of iron based on the formation of a ternary complex with 1,10-phenanthroline as a primary ligand and picrate as a counter ion. The slightly soluble red-orange complex obtained in the pH range 2-9 is easily and completely extracted into 1,2-dichloroethane. The absorbance is measured directly in the organic phase at 510 nm against a reagent blank. Beer’s law is obeyed over the concentration range 0.1-3.6 μg ml<sup>–1</sup>, corresponding to 0.01–0.36 μg ml<sup>–1</sup> of iron in the aqueous solution. The apparent molar absorptivity and Sandell’s sensitivity were 1.3 × 10<sup>5</sup> mol<sup>–1</sup> cm<sup>–1</sup> and 0.43 ng cm<sup>–2</sup>, respectively. The interference of various ions was examined and the serious interferences arising from common metal ions, which are sometimes unavoidable in other methods, were not observed in the proposed method. © Royal Society of Chemistry

Simultaneous determination of copper and iron by solvent extraction and first derivative spectrophotometry

A simple, sensitive and selective first derivative spectrophotometric method has been developed for the determination of copper and iron in mixtures. The method is based on the recovery of the analytes, by liquid-liquid extraction, Integrated reaction with 5-pheny1-3-(4-pheny1-2-pyridiny1)- l,2,4-triazine (PPT) and perchlorate in dichioroethane and on the subsequent direct derivative spectrophotometric measurement using the zero-crossing approach for determination of both analytes. Copper and Iron were thus determined in the ranges 50 - 2500 ng/ml and 2–120 ng/ml, respecttvely, in the presence of one another. The detection limits achieved (3σ) were found to be 17 ng/ml of copper and 0.7 ng/ml of iron. The relative standard deviations were in all instances less than 3.1%. The proposed method was applied to the determination of both analytes in well water and the results were consistent with those provided by the AAS standard method

A new Cu(II)- 5-(4-sulphophenylazo)-8-aminoquinoline complex used for copper determination in presence of gold and silver in water and mineral samples

In this work, a characterization of reagent chromophere 5-(4-sulphophenylazo)-8-aminoquinoline [SPA] by IR and 1H RMN was carried out and a pKa value of 3.55 ± 0.03 was found as well. An 1:2 stoichiometry for the Cu(II)-SPA complex was determined at pH 9 by Job and molar ratio methods. A value of 1.4 × 1014 for the stability constant was also found. Based on the formation of this complex a new method for the copper determination in presence of gold and silver was developed by derivative spectrophotometry using a previous preconcentration on solid phase. In this method, the analytical measures were executed directly in the solid phase containing the complex. The Cu(II) reacts with the reagent chromophere SPA previously retained in the anionic exchange DEAE Sephadex A25. In this determination, the first derivative at 605 nm was used. The quantification range was between (3.2 ± 0.3 × 10−1) × 10−8 and (94.4 ± 0.9) × 10−8 mol L−1 (3.2 ± 0.3 × 10−1) × 10−8 , and (94.4 ± 0.9) × 10−8 mol L−1. The repeatability expressed as RSD was between 1.1 and 2.0%. The method was applied successfully for the copper determination in mineral residuals and natural water samples. The results were consistent with those provided by ICP-mass spectrometr

Rotating disk sorptive extraction of cu-bisdiethyldithiocarbamate complex from water and its application to solid phase spectrophotometric quantification

This study demonstrates the first use of polydimethylsiloxane (PDMS) immobilized on a rotating disk for the extraction of copper from aqueous matrices and its subsequent direct determination by solid phase UV-Visible spectrophotometry. To accomplish the solid-phase extraction and the direct solvent-free spectrophotometric measurement, sodium diethyldithiocarbamate (NaDDTC) was used as an analytical reagent to form the uncharged chromophore complex Cu(DDTC)2, which absorbs at 432 nm. Different physicochemical conditions (pH, temperature, reagent concentration, chemical modifiers) and hydrodynamic factors (rotation velocity, extraction time, sample volume) were optimized. Under the optimized conditions, extraction equilibrium times of 30, 53 and 90 min were obtained for 100, 500 and 1000 mL of sample, respectively, with preconcentration factors of 286, 712 and 1284, respectively. The methodology was precise (repeatability and reproducibility of 7.2 and 8.4%, respectively, as relative st

A New Kinetic Spectrophotometric Method for the Quantitation of Amorolfine

Amorolfine (AOF) is a compound with fungicide activity based on the dual inhibition of growth of the fungal cell membrane, the biosynthesis and accumulation of sterols, and the reduction of ergosterol. In this work a sensitive kinetic and spectrophotometric method for the AOF quantitation based on the AOF oxidation by means of KMnO4 at 30 min (fixed time), pH alkaline, and ionic strength controlled was developed. Measurements of changes in absorbance at 610 nm were used as criterion of the oxidation progress. In order to maximize the sensitivity, different experimental reaction parameters were carefully studied via factorial screening and optimized by multivariate method. The linearity, intraday, and interday assay precision and accuracy were determined. The absorbance-concentration plot corresponding to tap water spiked samples was rectilinear, over the range of 7.56 × 10−6–3.22 × 10−5 mol L−1, with detection and quantitation limits of 2.49 × 10−6 mol L−1 and 7.56 × 10−6 mol L−1, respectively. The proposed method was successfully validated for the application of the determination of the drug in the spiked tap water samples and the percentage recoveries were 94.0–105.0%. The method is simple and does not require expensive instruments or complicated extraction steps of the reaction product