Kinetic determination of pyrogallol by a novel oscillating chemical reaction catalyzed by a tetraazamacrocyclic complex

A new analytical method for the determination of pyrogallol, by the perturbation caused by different amount of pyrogallol on a novel oscillation system is reported. This novel oscillation system, which is of Belousov–Zhabotinskii-type, involves a macrocyclic complex [CuL](ClO4)2 as catalyst and malic acid as the substrate. The ligand L in the complex is 5,7,7,12,14,14-hexemethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene. The experimental results show that the change in the amplitude of the potentiometric oscillation is linearly proportional to the logarithm of the concentration of pyrogallol in the range 1.5 × 10−6 to 1 × 10−4 M, with a correlation coefficient of 0.9959. The obtained relative standard deviation (R.S.D.) with eight samples is 1.6%. Some aspects of the potential mechanism of action of pyrogallol on the oscillating chemical system are also discussed.