New method for the spectrophotometric determination of phosphate as molybdenum blue using ferrous ammonium sulphate as reducing agent

A method for the microdetermination of calcium, phosphate, and arsenate in mixtures of the three has been developed. In an aliquot of the mixture calcium was determined complexometrically using EDTA. Phosphate and arsenate were determined in second and third aliquots, respectively, using spectrophotometric methods. The interference of arsenate in the determination of phosphate was avoided by masking arsenate with thiosulphate. The kinetics of formation of molybdenum blue from molybdoarsenic acid by reduction with ferrous ammonium sulphate was also studied. The rate-determining step was found to be the reduction of molybdoarsenic acid with iron(II); the reaction was first order in iron(II) and arsenate over the concentration ranges studied. Values found for the enthalpy, entropy, and free energy of activation were 22, 0.05, and 7.5 kcal, respectively.

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The volumetric determination of nitric acid in mixed and refuse acids: a reference half-cell for use in titrations with ferrous ammonium sulphate

The Analyst ◽

10.1039/an9487300669 ◽

1948 ◽

Vol 73 (873) ◽

pp. 669 ◽

Cited By ~ 8

Author(s):

C. R. N. Strouts ◽

C. A. Macinnes

Keyword(s):

Nitric Acid ◽

Ammonium Sulphate ◽

Ferrous Ammonium Sulphate ◽

Half Cell ◽

Volumetric Determination ◽

Ferrous Ammonium

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Determination of the electric field gradient tensor in ferrous ammonium sulphate using a polarized Mossbauer source

Journal of Physics C Solid State Physics ◽

10.1088/0022-3719/8/2/015 ◽

1975 ◽

Vol 8 (2) ◽

pp. 229-235 ◽

Cited By ~ 5

Author(s):

T C Gibb

Keyword(s):

Electric Field ◽

Electric Field Gradient ◽

Field Gradient ◽

Ammonium Sulphate ◽

Electric Field Gradient Tensor ◽

Ferrous Ammonium Sulphate ◽

Gradient Tensor ◽

Ferrous Ammonium

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SPECTROSCOPIC AND VOLUMETRIC TECHNIQUES FOR THE ESTIMATION OF IVABRADINE IMPURITY 3,3'-(PROPANE-1,3-DIYL)BIS(7,8-DIMETHOXY-1,3,4,5-TETRAHYDRO-2H-BENZO[D]AZEPIN-2-ONE)

International Journal of Applied Pharmaceutics ◽

10.22159/ijap.2019v11i3.31953 ◽

2019 ◽

pp. 216-218

Author(s):

S. ANIL KUMAR ◽

B. L. BHASKAR

Keyword(s):

Ammonium Sulphate ◽

Parent Drug ◽

Ferrous Ammonium Sulphate ◽

Subsequent Reaction ◽

Drug Molecule ◽

Reagent Blank ◽

Colored Complex ◽

Coloured Complex ◽

Ferrous Ammonium

Objective: Two simple and sensitive techniques - one spectrophotometric and one titrimetric- have been developed for the determination of 3,3'-(propane-1,3-diyl)bis(7,8-dimethoxy-1,3,4,5-tetrahydro-2H-benzo[d]azepin-2-one) commonly known as ivabradine impurity-9 (IVA-9). Methods: The spectrophotometric method is based on the oxidation of drug impurity by excess cerium (IV) sulphate in acidic medium and the subsequent reaction of the remaining Ce(IV) with a known amount of ferrous ammonium sulphate. The resultant ferric ion is then made to react with thiocyanate in acid medium to form a brown coloured complex which is analyzed spectrophotometrically against the reagent blank. In the volumetric method, the un-reacted Ce(IV) is titrated against standard ferrous ammonium sulphate to estimate the quantity of IVA-9. Results: The colored complex showed an absorption maximum at 479 nm when measured spectrophotometrically. The stated methods are validated statistically using the International Council for Harmonization guidelines-ICH Q2(R1) for precision and accuracy. The method showed a linear response from 0.5 to 100µg/ml with a correlation coefficient of 0.9985 Conclusion : No estimation techniques have been reported to date for the determination of this molecule. The proposed techniques may be used for the routine quantification in its pure form and also in presence of its parent drug molecule Ivabradine.

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