Complexometric analysis of magnetic materials by means of automatic titrations

Abstract

An analytical method based on automatic potentiometric titrations was developed for the analysis of magnetic material (e.g., Ba₂Zn₂Fe₁₂O₂₂). The elements were separated by extracting iron(III) as its chloride in diisopropyl ether and by precipitating barium as its sulphate in the presence of disodium dihydrogen ethylenediaminetetraacetate (EDTA). After separation, the iron and zinc were complexed with EDTA, buffered at pH 5 with ammonium acetate solution and back-titrated with standard iron(III) chloride solution by using platinum-wire and saturated calomel electrodes. Barium sulphate was dissolved in EDTA and ammonia solution, buffered at pH 10·1 and back-titrated with standard zinc nitrate solution at mercury|mercury-EDTA and saturated calomel electrodes. A complete analysis of the magnetic material was performed on as little as 10 mg of sample. A Tacussel Titrimat automatic titrator was used for all of the determinations. Results accurate to within 0·35 per cent. were obtained. A similar procedure can also be used to analyse different magnetic samples.