Determination of Ascorbic acid by Using a Belousov- Zhabotinsky Oscillating System Catalyzed by a Macrocylic Complex

摘要

An appropriate analytical technique for determination of ascorbic acid (AA) by its perturbation effecton Belousov-Zhabotinskii (BZ) oscillating system was reported in this article. The macrocyclic copper(II) complex ([Cul(ClO 4 ) 2 ]) was used as a catalyst while malic acid as substrate in BZ system. The ligandL in the macrocyclic-complex is 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene.Experimental outcomes shown the perturbation effect of AA could cause the change in the amplitude ofoscillation (?A) and change in the period of oscillation (?T) which were directly related to itsconcentration (3 × 10 -6 to 1.05 × 10 -4 M) with correlation coefficient of 0.99 respectively. The calculatedrelative standard deviation (RSD) is 2.71 % by eight samples (1.2 × 10 -5 M) and the observed lower limitof detection is 1.5 × 10 -6 M. The cyclic voltammetry (CV) experiments were used to confirm the redoxreaction between ascorbic acid and sodium bromate. Furthermore, the reaction perturbation mechanism,was derived from the well-known FKN (Field-Koros-Noyes) oscillation mechanism.