Spectrofluorimeteric Determination of Oxalate Based on Its Ternary Complex Between Eu3+ and Thenoyltrifluoroacetone

A simple, sensitive and selective determination method of oxalate has been investigated based on the fluorescence enhancement of $Eu^{3+}$-TTA complex due to the formation of $Eu^{3+}$-TTA-oxalate ternary complex. An emission peak of $Eu^{3+}$-TTA, which is increased linearly with addition of oxalate, occurs at 610 nm in aqueous solution with excitation at 306 nm. The linear range of the calibration curve is 1 ${\times}$$10^{-6}$-8 ${\times}$$10^{-6}$ M and the detection limit is 1 ${\times}$$10^{-6}$ M. The effects of foreign ions were studied. The present method was applied to determine oxalate of two synthetic samples.