Abstract: Arrangement and method for detecting the end of life of an aqueous bath utilized in semiconductor processing, the bath containing water, an amount of hydrogen peroxide and an amount of a predetermined chemical species, which is either an acid or a base, in accordance with the following steps: adding a predetermined additional amount of the hydrogen peroxide and/or the predetermined chemical species at predetermined time intervals, measuring at least one parameter of the aqueous bath, thereby obtaining a measured parameter value, the at least one parameter being selected from a set of parameters including bath pH and bath conductivity; reading a predicted value of said at least one parameter from a memory storing a curve of predicted values of said at least one parameter as a function of time, said curve depending on said predetermined additional amount of said hydrogen peroxide and/or said predetermined chemical species, and depending on said predetermined time intervals; establishing the end of life of said