Spectrophotometric determination of phosphate ions with the system cerium(III)Arsenazo III.
A new method for the spectrophotometric determination of PO(3-)(4), based on the conversion of the complex of cerium(III) with arsenazo III (CeH(4)R(-)) into CePO(4) is proposed and used for the indirect spectrophotometric determination of phosphorus in ferro-silicon. The reaction between Ce(III) and arsenazo III has been studied spectrophotometrically and the stability constants of the complex CeH(4)R(-) have been determined: log beta(1) = 6.42 +/- 0.10 (for pH 1-3) and log beta(1) = 6.11 +/- 0.02 (for pH 5.5-7).
Borissova
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R
Higher Institute of Chemical Technology, Department of Analytical Chemistry, Sofia-1156, Bulgaria.
Mitropolitska
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E