On the copper(II)-EDTA-par system for visual and photometric end-point detection in iron(III)-EDTA titrations.
The copper(II)-EDTA-PAR system is proposed as indicator for direct EDTA titration of 0.2-20 mg of iron(III) in acetic acid medium. The precision and accuracy have been evaluated by spectrophotometric titration. Microtitrations determine down to 10 mug of iron. A logarithmic concentration diagram has been constructed to present the complex equilibria involved. In an interference study the masking agent ammonium fluoride was found to improve the end-point detection. The method has been applied successfully to practical standard samples and compares favourably with other EDTA titrations of iron.
Nonova
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Department of Analytical Chemistry, University of Sofia, 1 Anton Ivanov Avenue, Sofia 26, Bulgaria.
Lihareva
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