Solvent extraction of niobium-4-(2-pyridylazo)resorcinol complex and spectrophotometric determination of niobium in oxalato solutions
Solvent extraction of niobium in the form of the pyridylazo resorcinol complex was studied. The strongly colored niobium complex which forms at pH 5.5 and contains 4-(2-pyridylazo)resorcinol and oxalate as ligands can be extracted into the chloroform by means of the tetraphenylarsonium and tetraphenylphosphonium chloride, respectively. The mechanism of the extraction is based on the formation of the ion-associated compounds that form between the hydrophobic organic cation and the oxo(oxalato)(pyridylazoresorcinolo)niobate(V) anion. The chloroform phase is more stable than the aqueous solutions of the complex, and it follows Beer's law in a significantly wider concentration range. A method was developed for the spectrophotometric determination of niobium in the organic phase after the chloroform extraction. This method has certain advantages over the niobium determination with 4-(2- pyridylazo)resorcinol in the aqueous oxalate medium. (auth)
- Research Organization:
- Univ., Zagreb
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-33-016613
- OSTI ID:
- 4100641
- Journal Information:
- Anal. Chem., v. 48, no. 1, pp. 55-59, Journal Name: Anal. Chem., v. 48, no. 1, pp. 55-59; ISSN ANCHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400104* --Chemistry--Analytical & Separations Chemistry-- Spectral Procedures
CHLOROFORM
INTERFERING ELEMENTS
N40120* --Chemistry--Analytical & Separations Chemistry-- Chemical & Spectral Procedures
NIOBIUM COMPLEXES
ORGANIC ARSENIC COMPOUNDS
ORGANIC CHLORINE COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
OXALATES
PYRIDYLAZORESORCINOL
QUANTITATIVE CHEMICAL ANALYSIS
SOLVENT EXTRACTION
TANTALUM
TITANIUM
URANIUM
ZIRCONIUM