scholarly journals 2-Hydroxy-4-Methoxybenzophenone Oxime as an Analytical Reagent for Copper(II)

2005 ◽  
Vol 2 (2) ◽  
pp. 161-164 ◽  
Author(s):  
Miss Krishna Purohit ◽  
K. K. Desai
Keyword(s):  
Molar Absorptivity ◽  
Complex Formation Reaction ◽  
Formation Reaction ◽  
Spectrophotometric Methods ◽  
Gravimetric Determination ◽  
Analytical Reagent ◽  
Gibb’S Free Energy ◽  
The Stability ◽  
Metal Ligand

2-Hydroxy-4-methoxybenzophenoneoxime (HMBO) was developed as a new analytical reagent for the gravimetric determination of Cu(II). In pH 2.5-9.0 the reagent gives brown coloured precipitate with Cu(II). Spectrophotometric methods revealed that the stoichiometry of the complex is 1:2 (metal: ligand). Beer's law is obeyed up to 31.75 ppm of Cu(II). Molar absorptivity and Sandell's sensitivity at 400 nm were found to be 7.0×102L mol-1cm-1and 0.090 μg/cm2respectively. The stability constant of Cu(II)-HMBO complex is found to be 6.13×109. Gibb’s free energy change for complex formation reaction was found to be -13.93 Kcal/mol. The reagent can be used for the analysis of brass.

scholarly journals 2-Hydroxy-5-methylbenzophenone oxime(HMBO) as an Analytical Reagent for Gravimetric Determination of Cu(II)

2007 ◽  
Vol 4 (1) ◽  
pp. 97-102 ◽  
Author(s):  
S. K. Shingadia ◽  
K. K. Desai
Keyword(s):  
Copper Ion ◽  
Molar Absorptivity ◽  
Ratio Method ◽  
Formation Reaction ◽  
Gravimetric Determination ◽  
Analytical Reagent ◽  
Gibb’S Free Energy ◽  
The Stability ◽  
Job's Method

2-Hydroxy-5-methylbenzophenone oxime (HMBO) was developed as a new analytical reagent for the gravimetric determination of divalent copper ion. In pH rang of 3.0 to 6.0, the reagent gives a buff colored precipitate with Cu(II). Job’s method and mole ratio method revealed that the stoichiometry of the complex is 1:2 (metal: ligand). Beer’s law is obeyed up to 61.25 ppm of Cu(II). Molar absorptivity and Sandell’s sensitivity at 400 nm were found to be 6.32 × 102L mol-1cm-1and 0.359 μg/cm2respectively. The stability constant of Cu(II)-HMBO complex is found to be 2.43 × 109. Gibb’s free energy change for complex formation reaction was found to be -12.88 Kcal/mol. The reagent can be used for the analysis of brass and alloy.

scholarly journals 2-Hydroxy-4-n-propoxy-5-bromoacetophenone oxime as an Analytical Reagent for Gravimetric Determination of V(V)

2009 ◽  
Vol 6 (2) ◽  
pp. 303-307 ◽  
Author(s):  
Ambily P. Nair ◽  
J. Christine
Keyword(s):  
Molar Absorptivity ◽  
Ratio Method ◽  
Gravimetric Determination ◽  
Pentavalent Vanadium ◽  
Analytical Reagent ◽  
Gibb’S Free Energy ◽  
The Stability ◽  
Ph Range ◽  
Job's Method

2-Hydroxy-4-n-propoxy-5-bromoacetophenone oxime (HnPBAO) was developed as a new analytical reagent for the gravimetric determination of pentavalent vanadium ion. In the pH range 4.0-6.0, the reagent gave a brown coloured precipitate with V(V). Job’s method and Mole ratio method revealed that the stoichiometry of the complex is 1:1 (metal: ligand). Beer’s law is obeyed up to 20.38 ppm of V(V). Molar absorptivity and Sandells sensitivity at 450 nm were found to be 10.22 × 102L/mol/cm and 0.049 µg/cm2respectively. The stability constant of V(V)-HnPBAO complex is found to be 1.195 × 106. Gibb’s free energy change for complex formation reaction was found to be –8.34 kcal/mol. The reagent can be used for the analysis of vanadium in ferro-vanadium alloys.

SIMPLE AND HIGHLY SELECTIVE DIRECT STABILITY INDICATING ULTRAVIOLET AND INDIRECT VISIBLE SPECTROPHOTOMETRIC METHODS FOR DETERMINATION OF ENROFLOXACIN IN PHARMACEUTICALS

2021 ◽  
Vol 88 (6) ◽  
pp. 982-992
Author(s):  
N. Rajendraprasad
Keyword(s):  
Standard Addition ◽  
Uv Degradation ◽  
Degradation Study ◽  
Formation Reaction ◽  
Stability Indicating ◽  
Spectrophotometric Methods ◽  
The Stability ◽  
Simple Economic ◽  
Molar Extinction Coefficients

Three simple, economic, selective and accurate and precise spectrophotometric methods are developed for determination of enrofloxacin (EFX) in pharmaceuticals. Method A is based on the measurement of absorbance of EFX in 0.1M HOAc at 315 nm. The ketoxime formation reaction has been employed in method B, in which the absorbance measurement of EFX oxime product at 275 nm is described. The third method (Method C) is indirect one and is based on the oxidation of EFX by cerium(IV), reaction of unreacted cerium(IV) with p-toludine (p-TD) and measurement of coloured solution at 540 nm. The Beer’s law is obeyed in the concentration ranges of 1.2–24, 1–8, and 1–20 μg/mL EFX in methods A, B, and C, respectively, with the corresponding molar extinction coefficients of 1.52×104, 3.86×104, and 6.6×103 L/mol/cm. The regression coefficients of calibration lines are 0.9996, 0.9913, and –0.9965, in methods A, B, and C, respectively. The limits of detection (LOD) and quantification (LOQ) have also been reported for each method. The methods have been validated to check accuracy, precision, robustness and ruggedness. The application of the methods proposed to determine EFX in tablets has been described and the results have been compared with a standard method. The results of validation and application have been found to be with excellent agreement. The standard addition procedure has been adopted in recovery experiments to further ascertain the accuracy of the methods and the results of the experiments are well satisfied. The stability indicating ability of Method A has been studied by subjecting EFX to acid and alkaline hydrolysis, oxidative, thermal and UV degradation followed by measurement of absorbance of resultant EFX solutions at 315 nm. The results of degradation study indicated unsusceptible nature of EFX to any of the stress conditions.

scholarly journals Sensitive Spectrophotometric Determination of Lamotrigine in Bulk Drug and Pharmaceutical Formulations using Bromocresol Green

2018 ◽  
Vol 35 (1) ◽  
pp. 55
Author(s):  
N. Rajendraprasad ◽  
K. Basavaiah ◽  
K. B. Vinay
Keyword(s):  
Potassium Hydroxide ◽  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Ion Pair ◽  
Bromocresol Green ◽  
Spectrophotometric Methods ◽  
Base Form ◽  
Bulk Drug ◽  
The Stability

Two new, simple, rapid and reproducible spectrophotometric methods have been developed for the determination of lamotrigine (LMT) both in pure form and in its tablets. The first method (method A) is based on the formation of a colored ion-pair complex (1:1 drug/dye) of LMT with bromocresol green (BCG) at pH 5.02±0.01 and extraction of the complex into dichloromethane followed by the measurement of the yellow ion-pair complex at 410 nm. In the second (method B), the drug-dye ion-pair complex was dissolved in ethanolic potassium hydroxide and the resulting base form of the dye was measured at 620 nm. Beer’s law was obeyed in the concentration range of 1.5-15 μg mL-1 and 0.5-5.0 μg mL-1 for method A and method B, respectively, and the  = corresponding molar absorptivity values are 1.6932 x 104 and 3.748 x 104L mol-1cm-1. The Sandell sensitivity values are 0.0151 and 0.0068 μg cm-2 for method A and method B, respectively. The stoichiometry of the ion-pair complex formed between the dug and dye (1:1) was determined by Job’s continuous variations method and the stability constant of the complex was also calculated. The proposed methods were applied successfully for the determination of drug in commercial tablets.

scholarly journals Charge Transfer Complexes of Ketotifen with 2,3-Dichloro-5,6-dicyano-p-benzoquinone and 7,7,8,8-Tetracyanoquodimethane: Spectroscopic Characterization Studies

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2039
Author(s):  
Gamal A. E. Mostafa ◽  
Ahmed Bakheit ◽  
Najla AlMasoud ◽  
Haitham AlRabiah
Keyword(s):  
Charge Transfer ◽  
Spectroscopic Characterization ◽  
Molar Ratio ◽  
Charge Transfer Complexes ◽  
Physical Parameters ◽  
Spectrophotometric Methods ◽  
Theoretical Approaches ◽  
The Stability ◽  
Ct Complexes

The reactions of ketotifen fumarate (KT) with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and 7,7,8,8-tetracyanoquinodimethane (TCNQ) as π acceptors to form charge transfer (CT) complexes were evaluated in this study. Experimental and theoretical approaches, including density function theory (DFT), were used to obtain the comprehensive, reliable, and accurate structure elucidation of the developed CT complexes. The CT complexes (KT-DDQ and KT-TCNQ) were monitored at 485 and 843 nm, respectively, and the calibration curve ranged from 10 to 100 ppm for KT-DDQ and 2.5 to 40 ppm for KT-TCNQ. The spectrophotometric methods were validated for the determination of KT, and the stability of the CT complexes was assessed by studying the corresponding spectroscopic physical parameters. The molar ratio of KT:DDQ and KT:TCNQ was estimated at 1:1 using Job’s method, which was compatible with the results obtained using the Benesi–Hildebrand equation. Using these complexes, the quantitative determination of KT in its dosage form was successful.

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.

scholarly journals Spectrophotometric Methods for the Assay of Pyrilamine Maleate Using Chromogenic Reagents

2010 ◽  
Vol 7 (4) ◽  
pp. 1507-1513 ◽  
Author(s):  
V. Annapurna ◽  
G. Jyothi ◽  
V. Nagalakshmi ◽  
B. B. V. Sailaja
Keyword(s):  
Charge Transfer ◽  
Oxidative Coupling ◽  
Coupling Reaction ◽  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Method Of Least Squares ◽  
Spectrophotometric Methods ◽  
Oxidative Coupling Reaction ◽  
Charge Transfer Complexation

Simple, accurate and reproducible UV spectrophotometric methods were established for the assay of pyrilamine maleate (PYRA) based on the formation of oxidative coupling and precipitation, charge transfer complexation products. Method A includes the oxidative coupling reaction of PYRA with 3-methyl-2-benzathiazolinone hydrazone (MBTH) in presence of Ce(IV). The formation of oxidative coupling product with 4-amino phenazone (4-AP) in presence of K3Fe(CN)6is incorporated in method B. Precipitation/charge transfer complex formation of the PYRA with tannic acid (TA)/Metol-Cr(VI) in method C were proposed. The optical characteristics such as Beers law limits, molar absorptivity and Sandell’s sensitivity for the methods (A-C) are given. Regression analysis using the method of least squares was made to evaluate the slope (b), intercept (a) and correlation coefficient (r) and standard error of estimation (Se) for each system. Determination of pyrilamine in bulk form and in pharmaceutical formulations were also incorporated.

scholarly journals Determination of Traces of Pd(II) in Spiked Samples by Using 3,4-Dihydroxybenzaldehydeisonicotinol-hydrazone as a Chelating Agent with UV Visible Spectrophotometer

2011 ◽  
Vol 8 (1) ◽  
pp. 217-225 ◽  
Author(s):  
S. Lakshmi Narayana ◽  
C. Ramachandraiah ◽  
A. Varada Reddy ◽  
Dongyeun Lee ◽  
Jaesool Shim
Keyword(s):  
Metal Ion ◽  
Regression Coefficient ◽  
Chelating Agent ◽  
Molar Absorptivity ◽  
Inexpensive Method ◽  
Colored Complex ◽  
Major Cations ◽  
Uv Visible ◽  
Metal Ligand

A simple, rapid, sensitive and inexpensive method has been developed for the determination of trace amounts of palladium(II) using 3,4-dihydroxybenzaldehydeisonicotinoylhydrazone (3,4-DHBINH). The metal ion gives a yellow colored complex with 3,4-DHBINH in acetate buffer of pH 3.0 with 1:1 (metal: ligand) composition. The complex shows maximum absorption at 380 nm. Beer’s law is obeyed in the range 0.5-20.0 ppm of Pd(II). The molar absorptivity, Sandell’s sensitivity and detection limit were found to be 0.53×104L mol-1cm-1, 0.02 μg cm-2and 0.0948 μg mL-1, respectively. The correlation coefficient and regression coefficient of the Pd(II)-3,4-DHBINH complex were 1.08 and 0.04 respectively. Major cations and anions did not show any interference. Anti-microbial activity of the Pd(II)-3,4-DHBINH has been studied. The developed method has been successfully applied to the analysis of Pd(II) in spiked samples. Comparing the results with those obtained using an atomic absorption spectrophotometer tested the validity of the method

Sign in / Sign up

Export Citation Format

Share Document