This document describes an analytical method for the electrochemical measurement of pure plutonium nitrate solutions of nuclear grade, with an expanded uncertainty not exceeding ±0,2 % at the confidence level of 0,95 for a single determination (coverage factor, k = 2). The method is suitable for aqueous solutions containing plutonium at more than 0,5 g/L and test samples containing plutonium between 4 mg and 15 mg. Application of this technique to solutions containing plutonium at less than 0,5 g/L and test samples containing plutonium at less than 4 mg requires experimental demonstration by the user that applicable data quality objectives will be met. For some applications, the purification of test samples by anion exchange is required before measurement to remove interfering substances present in significant amounts. Clause 10 provides a discussion of interferences and corrective actions. Purification is also appropriate in situations where the purity of the test sample is unknown or when it may fluctuate unpredictably in a manufacturing process. Clause 11 discusses the changes in application of the method and methodology that can be applied and important considerations when selecting measurement parameters, while still remaining within the intended scope of this document.