Extraction and spectrophotometric determination of molybdenum(VI) with N-phenylbenzohydroxamic acid and phenylfluorone

1987 ◽  
Vol 65 (5) ◽  
pp. 1124-1127 ◽  
Author(s):  
H. Dasaratha Gunawardhana ◽  
S. Amarasiri Fernando
Keyword(s):  
Hydrochloric Acid ◽  
Steel Sample ◽  
Chloroform Extract ◽  
Molar Absorptivity ◽  
Hydrochloric Acid Medium ◽  
Coloured Complex ◽  
Method Of Continuous Variation ◽  
Job's Method ◽  
Standard Steel

N-Phenylbenzohydroxamic acid reacts with molybdenum(VI) in 3.5–6.0 M hydrochloric acid to give a complex that is extractable into chloroform. The chloroform extract of the molybdenum complex, on second extraction from a dilute hydrochloric acid medium (0.2–0.3 M) in the presence of phenylfluorone and ethanol, forms an intensely coloured complex possessing an absorption maximum at 518 nm. Job's method of continuous variation reveals that the complex is Mo(VI)—2NPBHA—PF. The molar absorptivity under optimum conditions is 7.4 × 104 cm3 mol−1 cm−1. The system obeys Beer's law up to 0.6 ppm of molybdenum(VI). Considerable amounts of many cations and anions can be tolerated. The interference from vanadium(IV) and vanadium(V) can be eliminated by the addition of sodium metabisulphite, whereas the interference from titanium(IV) is mitigated by oxalate ions. The method has been successfully applied for the determination of molybdenum in a standard steel sample.

Extractive Spectrophotometric Method for the Determination of Glibenclamide by Ion-Pair Complex in Pure Form and Pharmaceutical Formulation

2019 ◽  
Vol 9 (o3) ◽  
Author(s):  
RUAA MUAYAD MAHMOOD ◽  
HAMSA MUNAM YASSEN ◽  
SAMAR , NAJWA ISSAC ABDULLA AHMED DARWEESH ◽  
NAJWA ISSAC ABDULLA
Keyword(s):  
Spectrophotometric Method ◽  
Molar Absorptivity ◽  
Ion Pair ◽  
Pharmaceutical Formulation ◽  
Ratio Method ◽  
Colored Complex ◽  
Colored Product ◽  
Method Of Continuous Variation ◽  
Job's Method

Simple, rapid and sensitive extractive spectrophotometric method is presented for the determination of glibenclamide (Glb) based on the formation of ion-pair complex between the Glb and anionic dye, methyl orange (MO) at pH 4. The yellow colored complex formed was quantitatively extracted into dichloromethane and measured at 426 nm. The colored product obeyed Beer’s law in the concentration range of (0.5-40) μg.ml-1. The value of molar absorptivity obtained from Beer’s data was found to be 31122 L.mol-1.cm-1, Sandell’s sensitivity value was calculated to be 0.0159 μg.cm-2, while the limits of detection (LOD) and quantification (LOQ) were found to be 0.1086 and 0.3292 μg.ml-1, respectively. The stoichiometry of the complex created between the Glb and MO was 1:1 as determined via Job’s method of continuous variation and mole ratio method. The method was successfully applied for the analysis of pharmaceutical formulation.

scholarly journals Development and Validation of an Extractive Spectrophotometric Method for Miconazole Nitrate Assay in Pharmaceutical Formulations

2018 ◽  
Vol 2018 ◽  
pp. 1-5
Author(s):  
Tadele Eticha ◽  
Getu Kahsay ◽  
Teklebrhan Hailu ◽  
Tesfamichael Gebretsadikan ◽  
Fitsum Asefa ◽  
...  
Keyword(s):  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Bromocresol Green ◽  
Ich Guidelines ◽  
Miconazole Nitrate ◽  
Method Of Continuous Variation ◽  
Development And Validation ◽  
Job's Method ◽  
Full Factorial

A simple extractive spectrophotometric technique has been developed and validated for the determination of miconazole nitrate in pure and pharmaceutical formulations. The method is based on the formation of a chloroform-soluble ion-pair complex between the drug and bromocresol green (BCG) dye in an acidic medium. The complex showed absorption maxima at 422 nm, and the system obeys Beer’s law in the concentration range of 1–30 µg/mL with molar absorptivity of 2.285 × 104 L/mol/cm. The composition of the complex was studied by Job’s method of continuous variation, and the results revealed that the mole ratio of drug : BCG is 1 : 1. Full factorial design was used to optimize the effect of variable factors, and the method was validated based on the ICH guidelines. The method was applied for the determination of miconazole nitrate in real samples.

scholarly journals A Sensitive Spectrophotometric Determination of Ritodrine, Pentazocine, Isoxsuprine Hydrochlorides and Amoxicillin in Pure and Pharmaceutical Samples

2008 ◽  
Vol 5 (1) ◽  
pp. 100-106 ◽  
Author(s):  
H. D. Revanasiddappa ◽  
M. A. Veena
Keyword(s):  
Acid Medium ◽  
The United States ◽  
Molar Absorptivity ◽  
United States Pharmacopoeia ◽  
Hydrochloric Acid Medium ◽  
Subsequent Determination ◽  
Highly Sensitive ◽  
Coloured Complex ◽  
Chloramine T

A simple, accurate and highly sensitive spectrophotometric method for the determination of ritodrine hydrochloride (RTH), pentazocine hydrochloride (PZH), isoxsuprine hydrochloride (ISH) and amoxicillin (AMX) is described. The method is based on the oxidation of the studied drugs by a known excess of chloramine – T (CAT) in hydrochloric acid medium and subsequent determination of the unreacted oxidant by reacting it with iodide in the same acid medium liberates iodine, which subsequently react with starch to form a stable starch-iodine complex. The reacted oxidant corresponds to the drug content. The coloured complex exhibits a maximum absorption at 590 nm. The apparent molar absorptivity values and Sandell’s sensitivity values are in the range 6.96x104- 1.43x105L mol–1cm–1and 2.45-4.30 ng cm–2, respectively. The method was successfully applied to the studied drugs in their dosage forms. The results are reproducible within ±1% and compare favorably with those of official methods of British Pharmacopoeia and the United States Pharmacopoeia.

scholarly journals Solvent Extraction And Spectrophotomteric Determination Of Cu(Ii) With Dicyclohexyl - 18- Crown-6

2013 ◽  
Vol 10 (3) ◽  
pp. 997-1004
Author(s):  
Baghdad Science Journal
Keyword(s):  
Aqueous Solution ◽  
Solvent Extraction ◽  
Correlation Coefficient ◽  
Extraction Efficiency ◽  
Molar Absorptivity ◽  
Liquid Extraction ◽  
Liquid Liquid Extraction ◽  
Coloured Complex

Liquid-Liquid Extraction of Cu(II) ion in aqueous solution by dicyclohexyl-18-crown-6 as extractant in dichloroethane was studied .The extraction efficiency was investigated by a spectrophometric method. The reagent form a coloured complex which has been a quantitatively extracted at pH 6.3. The method obeys Beer`s law over range from (2.5-22.5) ppm with the correlation coefficient of 0.9989. The molar absorptivity the stoichiometry of extracted complex is found to be 1:2. the proposed method is very sensitive and selective.

scholarly journals Spectrophotometric determination of metoclopramide hydrochloride in pharmaceutical tablets, by diazotization-coupling method with 1-naphthol as the coupling agent

2010 ◽  
Vol 7 (1) ◽  
pp. 704-712
Author(s):  
Baghdad Science Journal
Keyword(s):  
Detection Limit ◽  
Azo Dye ◽  
Diazonium Salt ◽  
Molar Absorptivity ◽  
British Pharmacopoeia ◽  
Pharmaceutical Tablets ◽  
Hydrochloric Acid Medium ◽  
Metoclopramide Hydrochloride ◽  
Sensitive Spectrophotometric Method

Simple, rapid and sensitive spectrophotometric method was proposed for the analysis of metoclopramide hydrochloride (MPH) in pure form as well as in pharmaceutical tablets. The method is based on the diazotization reaction of MPH with sodium nitrite in hydrochloric acid medium to form diazonium salt, which is coupled with 1-naphthol in sodium hydroxide medium to form azo dye, showing absorption maxima at 550 nm. Beer’s law is obeyed in the concentration range of 0.4 – 18 µg mL-1 of MPH with detection limit 0.5448 µg mL-1. The molar absorptivity and Sandell’s sensitivity are 3.4969 × 104 L mol-1 cm-1 and 0.0101 µg cm-2, respectively. The method was successfully applied to the determination of MPH in pharmaceutical tablets without any interference from common excipients used as additives in tablets. The results agree favorably with the official British Pharmacopoeia method.

scholarly journals Sensitive Spectrophotometric Methods for the Determination of Ascorbic Acid

2008 ◽  
Vol 5 (1) ◽  
pp. 10-15 ◽  
Author(s):  
H. D. Revanasiddappa ◽  
M. A. Veena
Keyword(s):  
Ascorbic Acid ◽  
Acid Medium ◽  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Spectrophotometric Methods ◽  
Maximum Absorbance ◽  
Hydrochloric Acid Medium ◽  
Subsequent Determination ◽  
Sulphuric Acid Medium

Two simple and sensitive spectrophotometric methods (A and B) have been described for the determination of ascorbic acid. Method A is based on the oxidation of ascorbic acid (AA) by known excess of Se(IV) in hydrochloric acid medium and subsequent determination of unreacted Se(IV) by reacting it with iodide in the same acid medium to liberate iodine, which react with starch to form a stable blue coloured iodine-starch complex, which shows maximum absorbance at 590 nm. Method B is based on the oxidation of ascorbic acid (AA) by known excess of Cr(VI) in sulphuric acid medium and the determination of unreacted Cr(VI) with diphenyl carbazide (DPC) under the same acidic medium to produce a stable red-violet coloured species, which shows a maximum absorbance at 550 nm. The reacted oxidants (in methods A and B) correspond to the AA content. The apparent molar absorptivity values are found to be 1.627×104and 1.641×104L mol-1cm-1for methods A and B, respectively. The proposed methods are simple, sensitive and suitable for the routine analysis of AA in pharmaceutical formulations and in real samples.

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 Kinetic determination of ultratrace amounts of iodide in perchloric-hydrochloric acid medium

1972 ◽  
Vol 21 (9) ◽  
pp. 1169-1173 ◽  
Author(s):  
Tsutomu FUKASAWA ◽  
Masaaki IWATSUKI ◽  
Keiko UESUGI
Keyword(s):  
Hydrochloric Acid ◽  
Acid Medium ◽  
Kinetic Determination ◽  
Hydrochloric Acid Medium

Capillary electrophoresis facilitates determination of metal complex stoichiometry by Job’s method of continuous variation

2013 ◽  
Vol 10 (5) ◽  
pp. 409 ◽  
Author(s):  
Nathan E. Boland ◽  
Alan T. Stone
Keyword(s):  
Capillary Electrophoresis ◽  
Chelating Agent ◽  
Formation Constants ◽  
Continuous Variation ◽  
Spectroscopic Characteristics ◽  
Peak Areas ◽  
Method Of Continuous Variation ◽  
Job's Method ◽  
Metal Ligand

Environmental context Knowledge of metal-chelating agent speciation is integral to our ability to predict and interpret the behaviour of synthetic chelating agents in the environment. Capillary electrophoresis can be used to separate metal–ligand complexes with similar spectroscopic characteristics but different stoichiometries, thereby providing insight into metal–ligand speciation that is not possible by any other technique. Here, we demonstrate the utility of capillary electrophoresis for the determination of metal–ligand stoichiometries and evaluate its limitations. Abstract Job’s method of continuous variation is a traditional method used to determine the stoichiometry of metal–ligand complexes. The method is often applied to whole-sample absorbance measurements but its utility is limited when two or more complexes are present at significant concentrations and have similar absorption spectra. Here we employ capillary electrophoresis (CE), which separates complexes on the basis of charge and hydrodynamic radii, to extend the capabilities of Job’s method. Solutions containing nickel(II) and diethylenetriaminepentaacetic acid (DTPA) yield three CE peaks. Job’s method plot maxima, based on areas for each of the three CE peaks, coincide with nickel(II)-to-DTPA ratios of 1 : 1 and 1 : 2, which correspond to two complexes previously identified using whole-sample measurements, plus a ratio of 3 : 2, which corresponds to a previously unreported complex. We demonstrate how CE peak areas and electromigration times can be used to determine complex stoichiometries and formation constants. We discuss the strengths and weaknesses of Job’s Method coupled with CE and implications for speciation determination in environmentally relevant systems.

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