In this research improve the conditions determining zinc(II) using the method of optical spectroscopy based on the formation of a complex with BPT when the wavelength (430nm) and through the study of the impact of degrees pH the middle, and the effect of the interference caused by the presence of some of the nickel ions, iron(II) , calcium, copper, chromium, and manganese that hinder the process of identifying zinc-mediated this reagent .