The spectrophotometric determination of Troxerutin (TRXN) in sub-micromolar concentrations (135 nmol/L-1.06 mu mol/L) was accomplished using a coupled redox-complexation reaction with Ce(IV)-Arsenazo III, in the following order: a. Reduction of Ce(IV) by the TRXN analysed; b. Complexation of Ce(III) resulted by Arsenate III at pH 3.50; c. Absorptiometry of the [Ce(III)-Arsenazo III](3+) complex at lambda(1) = 615 nm and/or lambda(1) = 655 nm. The apparent molar absorptivities at lambda(1), lambda(2) were calculated as: epsilon(1) = 3.81 X 10(5) and epsilon(2) = 4.01 X 10(5)Lmol(-1) cm(-1), and Sandell's sensitivities were found to be Ss(1) = 1.9 and Ss(2) = 1.8 ngcm(-2) respectively. Beer's law was obeyed for both lambda(1), lambda(2) from 0.1-0.8 mu g TRXN/mL with a CV% equal to about 1.0. The accuracy and the precision of the method could be considered as very satisfactory, and the results obtained from the determination of TRXN, using the proposed new method and the 3-methylbenzothiazolin-2-one hydrazone one, both applied on samples of the same batches, were statistically analysed by means of Student's t-test and by the variance ratio F-test and found to show no significant difference.
