Abstract: A new quantitative analytical method for the determination of tyrosine by the perturbation caused by different amounts of tyrosine on the NaBrO3-Malic acid-[CuL](ClO4)2-H2SO4 oscillating chemical system is reported. The unsaturated ligand L in the complex [CuL](ClO4)2 is 5，7，7，12，14，14-hexemethyl-1，4，8，11-tetraazacyclotetradeca-4，11-diene. When different concentrations of tyrosine is injected into the oscillating chemical system, the mutation of the amplitude ΔAm fits a linear relationship to the logarithm of the concentration of tyrosine lg{[Tyr]0} in the range 1235×10-6~2677×10-4 mol/L very well. The correlation coefficient is 0999 18. The experimental results also show that there is the linear relationship between the change in the oscillating period ΔT of the chemical system and the logarithm of the concentration of tyrosine lg{[Tyr]0} in the range 7444×10-7~4534×10-4 mol/L. The correlation coefficient is 0993 61. The effect of influential variables, such as temperature, stirring rate and the concentration of components on the oscillating system are studied. Some aspects of the probable mechanism of perturbation of tyrosine on the oscillating chemical system are also discussed.

Key words: oscillating chemical system, tetrrazamacrocyclic complex, tyrosine, perturbation