This document specifies an analytical method by spectrophotometry, for determining the plutonium concentration in nitric acid solutions, with spectrophotometer implemented in hot cell and glove box allowing the analysis of high activity solutions. Commonly, the method is applicable, without interference, even in the presence of numerous cations, for a plutonium concentration higher than 0,5 mg·l"1 in the original sample with a standard uncertainty, with coverage factor k = 1, less than 5 %. The method is intended for process controls at the different steps of the process in a nuclear fuel reprocessing plant or in other nuclear facilities.