Abstract: A data processing method for differential rate kinetic analysis based on successive reactions is described.The method is a new kind of proportional equation established by using parameters of two reaction rates which are measured at different period of reaction times.The difference bet en two successive reactions can be exploited more extensively by using this method,and analysis accuracy can be increased.The simultaneous determination of epinephrine and norepinephrin in a mixture is performed by this method,errors found are obviously smaller than those obtained by traditional proportional equation and extension proportional equatin.

Key words: Successive reactions.Differential rate kinetic analysis, Proportional equation, Epinephrine, Norepinephring