scholarly journals Investigation of the extraction equilibrium of ion-association complexes of molybdenum (VI) with some polyphenols and thiazolyl blue. extraction-spectrophotometric determination of molybdenum

2005 ◽  
Vol 3 (4) ◽  
pp. 747-755 ◽  
Author(s):  
Atanas Dimitrov ◽  
Vania Lekova ◽  
Kiril Gavazov ◽  
Boyan Boyanov
Keyword(s):  
Organic Solvent ◽  
Aqueous Medium ◽  
Spectrophotometric Method ◽  
Ion Association ◽  
Extraction Process ◽  
Association Constants ◽  
Optimum Conditions ◽  
Extraction Equilibrium ◽  
Simple Extraction

AbstractThe extraction process of ternary ion-association complexes of molybdenum (VI) with some polyphenols (4-nitrocatechol, 2,3-dihydroxy naphthalene) and thiazolyl blue has been investigated by using an extraction-spectrophotometric method. The optimum conditions for their quantitative preparation in aqueous medium and subsequent extraction into an organic solvent have been found. The extraction, distribution and association constants, and the recovery factors have been calculated. The composition of the complexes has been determined. A precise, sensitive and simple extraction-spectrophotometric method for determination of molybdenum in products from ferrous metallurgy has been developed.

scholarly journals Spectrophptometric Analysis of Clathromycin with Tpooo, Ars and WFB

2020 ◽  
Vol 4 (1) ◽  
Keyword(s):  
Organic Solvent ◽  
Aqueous Phase ◽  
Organic Phase ◽  
Spectrophotometric Method ◽  
Ion Association ◽  
The Other ◽  
Optimum Conditions ◽  
Variable Parameters ◽  
Maximum Stability ◽  
Association Complex

One simple and sensitive procedure (simple spectrophotometric method) for the assay of drug clarithromycin in pure form and formulations. This method involves the formation of ion-association complex between CAM and the TPOOO, ARS and WFB. In order to establish the optimum conditions necessary for rapid and quantitative formation of coloured product with maximum stability and sensitivity, the author performed experiments by measuring the absorbance at λmax 480nm,420nm and580nm of respective series of solutions, varying one and fixing the other parameters in each case such as type, volume and concentration of acid, organic solvent used for extraction, ratio of organic phase to aqueous phase during extraction, shaking time and temperature. The variable parameters were optimized. The results were statistically validated.

Octahedral cobalt(III) complexes in dipolar aprotic solvents. III. A new spectrophotometric method for the determination of ion association constants

1966 ◽  
Vol 19 (1) ◽  
pp. 51 ◽  
Author(s):  
WA Millen ◽  
DW Watts
Keyword(s):  
Spectrophotometric Method ◽  
Association Constant ◽  
Ion Association ◽  
Chloride Ion ◽  
Association Constants ◽  
Aprotic Solvents ◽  
Extinction Coefficients ◽  
Ion Association Constants ◽  
Dipolar Aprotic Solvents

A spectrophotometric method for the evaluation of ion association constants has been developed. This method involves the preparation of solutions containing only the compound under consideration. A function relating the association constants to the concentration of compound and extinction coefficients has been derived. The association constants are best determined by an iterative method using a computer. The association constant for the cis-diohlorobisethylenediaminecobalt(111) cation, cis-[Co en2 Cl2]+, and chloride ion in NN-dimethylformamide (DMF) at 30� has been calculated by this new method and is compared with that of another established procedure. The association constant has also been determined for the association of cis-[Co en2 Cl2]+ and iodide in DMF at 30�.

Octahedral cobalt(III) complexes in dipolar aprotic solvents. II. Association between cis- and trans-dichlorobisethylenediamine cobalt(III) cations,[Co en2 Cl2]+, and chloride and bromide ions in the solvents NN-dimethylformamide, dimethyl sulphoxide, and LVN-dimethylacetamide

1966 ◽  
Vol 19 (1) ◽  
pp. 43 ◽  
Author(s):  
WA Millen ◽  
DW Watts
Keyword(s):  
Spectrophotometric Method ◽  
Ion Pairs ◽  
Ion Association ◽  
Ion Pair ◽  
Association Constants ◽  
Dimethyl Sulphoxide ◽  
Aprotic Solvents ◽  
Ion Association Constants ◽  
Cis And Trans ◽  
Dipolar Aprotic Solvents

Ion association constants at 30� have been determined for the cis-[Co en, Cl2]+Cl- ion pair in NN-dimethylformamide (DMF), NN-dimethylacetamide (DMA), and at 20.0�, 25.0�, and 30.0� in dimethyl sulphoxide (DMSO), by a spectrophotometric method. Association constants for the cis-[Co en2 Cl2]+Br- and the trans- [Co en2 Cl2]+Cl- ion pairs have also been determined in DMF at 30�.

Resonance Rayleigh Scattering for the Determination of Chlorpromazine and Promethazine

2006 ◽  
Vol 59 (12) ◽  
pp. 915 ◽  
Author(s):  
Lanxiang An ◽  
Shaopu Liu ◽  
Zhongfang Liu ◽  
Ling Kong ◽  
Xiaoli Hu
Keyword(s):  
Reaction Mechanism ◽  
Drug Concentration ◽  
Rayleigh Scattering ◽  
Ion Association ◽  
Resonance Rayleigh Scattering ◽  
Optimum Conditions ◽  
Serum Samples ◽  
Spectroscopic Characteristics ◽  
Urine And Serum

Chlorpromazine (CPZ) and promethazine (PZ) can react with potassium ferrioxalate (PF) to form 3:1 ion-association complexes, which can result in a significant enhancement of resonance Rayleigh scattering (RRS) intensity. The maximum scattering peaks are located at 368 nm for CPZ-PF and 370 nm for PZ-PF. The RRS spectroscopic characteristics, the optimum conditions of reactions, and influencing factors have been studied for CPZ-PF and PZ-PF. There is a linear relationship between the RRS intensity and the drug concentration in the range of 0.02–8.00 μg mL–1 for CPZ and 0.04–9.00 μg mL–1 for PZ, and the detection limits (3σ) are 6.6 ng mL–1 for CPZ and 10.6 ng mL–1 for PZ. The proposed method has been applied to determine CPZ in urine and serum samples with satisfactory results. Moreover, the reaction mechanism and the reasons for intensity enhancement of RRS have been discussed.

scholarly journals Preconcentration method for trace metals in natural waters using 4-morpholine dithiocarbamate

2002 ◽  
Vol 67 (12) ◽  
pp. 879-885 ◽  
Author(s):  
Zoran Todorovic ◽  
Predrag Polic ◽  
Tibor Sabo ◽  
Milorad Cakic
Keyword(s):  
Trace Metals ◽  
Organic Solvent ◽  
Water Samples ◽  
Natural Waters ◽  
Optimum Conditions ◽  
Metal Analysis ◽  
Preconcentration Method

The optimum conditions were found for the preconcentration of trace metals in natural waters and model samples with standard metals concentrations by using 4-morpholine dithiocarbamate. The formed complexes were extracted with chloroform. Different methods for recovering the metals from the organic solvent were studied and compared before AAS metal analysis. The developed preconcentration method was successfully applied to the determination of trace metals concentrations in water samples from the "Barje" lake (Leskovac, Yugoslavia).

scholarly journals A Sensitive Spectrophotometric Method for the Determination of Desloratadine in Tablets

2007 ◽  
Vol 90 (2) ◽  
pp. 372-375 ◽  
Author(s):  
Sena Çğalar ◽  
Aysel Öztun
Keyword(s):  
Spectrophotometric Method ◽  
Control Analysis ◽  
Optimum Conditions ◽  
Chromatography Method ◽  
Deep Blue ◽  
Quality Control Analysis ◽  
Significant Difference ◽  
Liquid Chromatography Method ◽  
First Time

Abstract A simple, rapid, and sensitive visible spectrophotometric method was developed, for the first time, for analysis of desloratadine (DE) in tablets. The method is based on the deep-blue colored TCNQ- radical anion formed by interaction of the drug (n-donor) with 7,7,8,8-tetracyanoquinodimethane (TCNQ, π-acceptor) in acetonitrile at ambient temperature. Optimum conditions for the reaction were investigated, absorbances were read at 843 nm, and the linearity range for concentrations of DE was found to be 1.5-13 μg/mL. The reaction product remains stable up to 8 h when kept at room temperature in the dark. The developed method was validated and successfully applied to the determination of DE in tablets. The tablets were also analyzed with a column liquid chromatography method reported in literature. The results from both methods were statistically compared by t- and F-tests. No significant difference was found for the means and standard deviations at 95% confidence level. Accuracy was examined through recovery studies. Being very simple and reliable, the method can be recommended for routine quality control analysis of DE in tablets.

Direct spectrophotometric method for the determination of cobalt with indane 1,2,3-trionetrioxime in aqueous medium

1987 ◽  
Vol 92 (1-3) ◽  
pp. 57-63 ◽  
Author(s):  
D. Mallikarjuna Rao ◽  
K. Hussain Reddy ◽  
D. Venkata Reddy
Keyword(s):  
Aqueous Medium ◽  
Spectrophotometric Method
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