scholarly journals Spectrophotometric Determination of Gold(III) Using 2-Hydroxy-3-Methoxy Benzaldehyde Thiosemicarbazone as a Chromophoric Reagent

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
D. Prem Kumar ◽  
A. Praveen Kumar ◽  
T. Veera Reddy ◽  
P. Raveendra Reddy
Keyword(s):  
Spectrophotometric Determination ◽  
Certified Reference Materials ◽  
Environmental Water ◽  
Molar Absorptivity ◽  
Zero Order ◽  
Gold Complex ◽  
Dimethyl Formamide ◽  
Spectrophotometric Methods ◽  
Benzaldehyde Thiosemicarbazone

A chromophoric reagent, 2-hydroxy-3-methoxy benzaldehyde thiosemicarbazone (HMBATSC), was employed for the sensitive spectrophotometric determination of gold(III). The gold(III) ion forms a blue-coloured complex with HMBATSC in an aqueous dimethyl formamide at pH 6.0. The gold complex shows the absorption maximum at 385 nm, and Beer's law was obeyed in the range 0.49–8.37 μg mL−1. The molar absorptivity and Sandell's sensitivity were found to be  L mol−1 cm−1 and 0.015 μg cm−2, respectively. The complex shows 1 : 1 [Au(III) : HMBATSC] stoichiometry with a stability constant of . The interference effect of various diverse ions has been studied. In addition to zero-order, first- and second-order derivative spectrophotometric methods were also developed for the determination of gold(III) in microgram amounts which were more sensitive than the zero-order method. The developed method has been used for the determination of gold(III) in environmental water samples and certified reference materials. The results were in excellent agreement with the certified values.

scholarly journals UV-Vis Spectrophotometric Determination of Selected Heavy Metals (Pb, Cr, Cd and As) in Environmental, Water and Biological Samples with Synthesized Glutaraldehyde Phenyl Hydrazone as the Chromogenic Reagent

2021 ◽  
Vol 2 (3) ◽  
pp. 1-5
Author(s):  
Samuel Echioda ◽  
Adepeju Oluwabunmi Ogunieye ◽  
Salisu Salisu ◽  
Amina Abdulazeez Abdulrasheed ◽  
I. Y. Chindo ◽  
...  
Keyword(s):  
Spectrophotometric Determination ◽  
Biological Samples ◽  
Environmental Water ◽  
Molar Absorptivity ◽  
Ligand Complex ◽  
Chromogenic Reagent ◽  
Validity Range ◽  
Metal Ligand ◽  
Water And Biological Samples

A simple, sensitive, selective, and non-extractive UV-Vis spectrophotometric method for the determination of cadmium, lead, chromium, and arsenic in biological, soil and water samples using synthesized and characterized phenyl hydrazone; glutaraldehydephenyl hydrazone (GPH) as the chromogenic reagent was developed. GPH was synthesized as new chromogenic analytical reagents for the direct UV-Vis spectrophotometric determination of the selected metals of interest in a slightly acidic pH of 6.5-7.5 and 20 % dimethylformamide (DMF) solution to give stable coloured metal-ligand complexes. The reactions were instantaneous; the wavelengths of maximum absorptions were followed spectrophotometrically and noted. The reagent GPH revealed a wavelength of maximum absorption between 360.0 (Cr) to 395.0 nm for (Pb and As) at a working pH of 6.5 to 7.5 room temperature (37 °C). The reagent GPH had a molar absorptivity (L mol-1 cm-1) ranging from 2.213×104 (Pb) to 2.460×104 (As), a mole ratio of metal to ligand of 2:1, the detection limit (µg/g) ranging from 0.3432 (As) to 0.5250 (Pb) and the metal-ligand complex was stable for 0-48 hours. The reagents had a Beer’s law validity range (mg L-1) of 0.001 to 100. The Sandell’s sensitivities (µg/cm2) ranged from 0000409 (As) to 0.00499 (Pb) for APDH and 0.00406 (As) to 0.00452 (Pb) respectively. Large excess of cations and anions as possible interferences up to 15 folds were studied and do not interfere with the determination of the selected metals of interest. The developed method is highly selective for Cd, Pb, and Cr and As and was successfully used for the determination for the said elements in soil, water, and biological samples. The results of the developed methods were comparable with AAS and were found to be in good agreement. The method had very high precision and very good accuracy.

scholarly journals Micelle-mediated extraction of cobalt and its spectrophotometric determination in rocks, soils, sediments and sea-bed polymetallic nodules

2019 ◽  
Author(s):  
Chem Int ◽  
Pranab Kumar Tarafder
Keyword(s):  
Spectrophotometric Determination ◽  
Certified Reference Materials ◽  
Molar Absorptivity ◽  
Present System ◽  
Sea Bed ◽  
Soil Sediment ◽  
Polymetallic Nodules ◽  
Ph Range ◽  
Almost All

The surfactant sensitized bottle-green complex (1:2:1) formed of cobalt-thiocyanate-cetyltrimethylammonium bromide is suitably extracted into an organic solvent, ethylacetate, at a pH range, 6-8 and the absorption measurements were carried out at 630 nm (ƛmax). The Beer’s law is obeyed in the range from 0.05 to 10 μg per mL. The molar absorptivity and Sandell’s sensitivity of the present system were found to be 2.2 x 103 L.mol-1cm-1 and 0.026 μg cm-2, respectively. No other element forms complex of similar colour with thiocyanate at this pH range. The method was applied to a number of samples like rock, soil, sediment, polymetallic nodules etc., as well as Certified Reference Materials and the values were found highly satisfactory. The interference of Fe3+ which formed a reddish complex at acidic pH (<7) was eliminated when the complex was extracted at pH 8.0. The method is highly useful for the determination of cobalt in geological samples having its concentration from μg/mL to percentage level. As the method has been made highly selective for spectrophotometric determination of cobalt, it might be applied to almost all types of geological sample of diverse matrices.

scholarly journals Micelle-mediated extraction of cobalt and its spectrophotometric determination in rocks, soils, sediments and sea-bed polymetallic nodules

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Spectrophotometric Determination ◽  
Certified Reference Materials ◽  
Molar Absorptivity ◽  
Present System ◽  
Sea Bed ◽  
Soil Sediment ◽  
Polymetallic Nodules ◽  
Ph Range ◽  
Almost All

The surfactant sensitized bottle-green complex (1:2:1) formed of cobalt-thiocyanate-cetyltrimethylammonium bromide is suitably extracted into an organic solvent, ethylacetate, at a pH range, 6-8 and the absorption measurements were carried out at 630 nm (ƛmax). The Beer’s law is obeyed in the range from 0.05 to 10 μg per mL. The molar absorptivity and Sandell’s sensitivity of the present system were found to be 2.2 x 103 L.mol-1cm-1 and 0.026 μg cm-2, respectively. No other element forms complex of similar colour with thiocyanate at this pH range. The method was applied to a number of samples like rock, soil, sediment, polymetallic nodules etc., as well as Certified Reference Materials and the values were found highly satisfactory. The interference of Fe3+ which formed a reddish complex at acidic pH (<7) was eliminated when the complex was extracted at pH 8.0. The method is highly useful for the determination of cobalt in geological samples having its concentration from μg/mL to percentage level. As the method has been made highly selective for spectrophotometric determination of cobalt, it might be applied to almost all types of geological sample of diverse matrices.

scholarly journals Spectrophotometric determination of ceftazidime in pharmaceuticals using resorcinol and 2-methylphenol

2021 ◽  
pp. 35-44
Author(s):  
O. Kostiv ◽  
◽  
O. Korkuna
Keyword(s):  
Hydrochloric Acid ◽  
Alkaline Medium ◽  
Spectrophotometric Determination ◽  
Molar Absorptivity ◽  
Azo Compounds ◽  
Azo Coupling ◽  
Spectrophotometric Methods ◽  
Maximum Absorbance ◽  
Stoichiometric Ratios

We developed two fast, simple and sensitive spectrophotometric methods for the determination of ceftazidime in drugs by using phenolic reagents resorcinol and 2-methylphenol. The methods are based on a previous antibiotic diazotization in the medium of hydrochloric acid (CHCl=12 M) and its following azo coupling with reagents in an alkaline medium with the formation of effective analytical forms that allow determining ceftazidime and have maximum absorbance at 519 nm and 516 nm for resorcinol and 2- methylphenol, respectively. The azo coupling products of diazotized ceftazidime exhibit effective molar absorptivity in the range of (6.31–6.84)103 M–1 cm–1. Stoichiometric ratios of the azo compounds components were established using continuous variations methods and they were the same in both cases (1:1). The developed methods allow determining from 2.75 to 185.5 g mL–1 of ceftazidime with resorcinol (LOQ=2.54 g mL–1) and 0.32191.3 g mL–1 of ceftazidime with 2-methylphenol (LOQ=0.28 g mL–1). The developed methods have been successfully tested in the analyses of one-component preparations (powders for injection solutions).

scholarly journals Spectrophotometric Determination of Carbamazepine in Pharmaceutical Formulations Based on its Reaction with a Brominating Agent

2019 ◽  
Vol 9 (2) ◽  
pp. 42-49
Author(s):  
Warda Rizgar ◽  
Diyar S. Ali
Keyword(s):  
Methylene Blue ◽  
Spectrophotometric Determination ◽  
General Procedure ◽  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Pure Form ◽  
Great Precision ◽  
Spectrophotometric Methods ◽  
Precision And Accuracy

Two accurate spectrophotometric methods described for the estimation of carbamazepine (CBZ) in both pharmaceutical and pure form. These methodologies are attached to the bromination of CBZ by bromine formed in instantly from the bromate-bromide reaction. The general procedure includes the additional of a known amount of bromate-bromide reagent in an acidic mediocre to CBZ. After the reaction is integrated, the unreacted bromine was reacted with a steady amount of methylene blue, and the absorbance was measured at 665 nm (method A) or, cresol red could be used for the reaction and the absorbance moderated at 517 nm (method B). Beer’s law was submitted from 0.45 to 15.00 μg/mL CBZ with a molar absorptivity of 4.93 × 103 L/mol.cm for method A and from 0.50 to 12.00 μg/mL CBZ with a molar absorptivity of 1.37 × 104 L/mol.cm for method B. The proposed methods were effective for the determination of CBZ in tablets with great precision and accuracy.

DC Polarographic and Spectrophotometric Determination of Ampicillin Capsules

1980 ◽  
Vol 63 (5) ◽  
pp. 1049-1051
Author(s):  
Juan A Squella ◽  
Luis J Nunez-Vergara ◽  
Maximo Aros
Keyword(s):  
Absorption Band ◽  
Spectrophotometric Determination ◽  
Degradation Product ◽  
Uv Absorption ◽  
Acidic Hydrolysis ◽  
Average Recovery ◽  
Polarographic Wave ◽  
Spectrophotometric Methods ◽  
Hydrolysis Of

Abstract Polarographic and spectrophotometric methods are proposed for the determination of ampicillin in capsules. Acidic hydrolysis of ampicillin with 1% HCHO in 0.3N HCl yields a degradation product identified as 2-hydroxy-3-phenyl-6-methylpyrazine. This compound has a well defined UV absorption band at 380 nm and a polarographic wave at –0.55 V vs SCE, which can be used for analytical purposes. Individual capsule assays, composite assays, and recovery studies are described. The average recovery values and standard deviations (SD) for UV and polarographic determinations were 99.20% (SD 0.95) and 100.85% (SD 1.09), respectively

scholarly journals Cerimetric determination of simvastatin in pharmaceuticals based on redox and complex formation reactions

2018 ◽  
Vol 33 (2) ◽  
pp. 21
Author(s):  
Kanakapura Basavaiah ◽  
Okram Zenita Devi
Keyword(s):  
Limit Of Detection ◽  
Reference Method ◽  
Standard Addition ◽  
Molar Absorptivity ◽  
Experimental Conditions ◽  
Spectrophotometric Methods ◽  
Fixed Quantity ◽  
Bulk Drug ◽  
Student’S T

Two sensitive spectrophotometric methods are described for the determination of simvastatin (SMT) in bulk drug and in tablets. The methods are based on the oxidation of SMT by a measured excess of cerium (IV) in acid medium followed by determination of unreacted oxidant by two different reaction schemes. In one procedure (method A), the residual cerium (IV) is reacted with a fixed concentration of ferroin and the increase in absorbance is measured at 510 nm. The second approach (method B) involves thereduction of the unreacted cerium (IV) with a fixed quantity of iron (II), and the resulting iron (III) is complexed with thiocyanate and the absorbance measured at 470 nm. In both methods, the amount of cerium (IV) reacted corresponds to SMT concentration. The experimental conditions for both methods were optimized. In method A, the absorbance is found to increase linearly with SMT concentration (r = 0.9995) whereas in method B, the same decreased (r = -0.9943). The systems obey Beer’s law for 0.6-7.5 and 0.5-5.0 μg mL-1 for method A and method B, respectively. The calculated molar absorptivity values are 2.7 X 104 and 1.06 X 105 Lmol-1 cm-1, respectively; and the corresponding sandel sensitivity values are 0.0153 and 0.0039μg cm-2, respectively. The limit of detection (LOD) and quantification (LOQ) are reported for both methods. Intra-day and inter-day precision, and accuracy of the methods were established as per the current ICH guidelines. The methods were successfully applied to the determination of SMT in tablets and the results were statistically compared with those of the reference method by applying the Student’s t-test and F-test. No interference was observed from the common excipients added to tablets. The accuracy and validity of the methods were further ascertained by performing recovery experiments via standard addition procedure.

scholarly journals SPECTROPHOTOMETRIC METHODS FOR DETERMINATION OF SOFOSBUVIR AND DACLATASVIR IN PURE AND DOSAGE FORMS

2021 ◽  
pp. 112-119
Author(s):  
MONIR Z. SAAD ◽  
ATEF AMER ◽  
KHALED ELGENDY ◽  
BASEM ELGENDY
Keyword(s):  
Indigo Carmine ◽  
Reference Method ◽  
Standard Addition ◽  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Experimental Conditions ◽  
Fixed Amount ◽  
Alizarin Red ◽  
Spectrophotometric Methods

Objective: Two simple, sensitive and accurate spectrophotometric methods have been developed for the determination of sofosbuvir (SOF) and daclatasvir (DAC) in pure forms and pharmaceutical formulations. Methods: The proposed methods are based on the oxidation of SOF and DAC by a known excess of cerium(IV) ammonium nitrate in sulphuric acid medium followed by determination of unreacted cerium(IV) by adding a fixed amount of indigo carmine (IC) and alizarin red S (ARS) dyes followed by measuring the absorbance at 610 and 360 nm, respectively. The experimental conditions affecting the reaction were studied and optimized. Results: The beer’s law was obeyed in the concentration ranges of 0.2-3.0, 0.2-4.0 for SOF and 0.5-4.5 and 0.5-5.0 μg/ml for DAC using IC and ARS methods, respectively with a correlation coefficient ≥ 0.9991. The calculated molar absorptivity values are 2.354 × 104, 1.933 × 104 for SOF and 1.786 × 104 and 2.015 × 104 L/mol. cm for DAC using IC and ARS methods, respectively u. The limits of detection and quantification are also reported. Intra-day and inter-day precision and accuracy of the methods have been evaluated. Conclusion: The methods were successfully applied to the assay of SOF and DAC in tablets and the results were statistically compared with those of the reference method by applying Student’s t-test and F-test. No interference was observed from the common tablet excipients. The accuracy and reliability of the methods were further ascertained by performing recovery studies using the standard addition method.

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