RAPID PHOTOMETRIC-DETERMINATION OF NEPTUNIUM WITH XYLENOL ORANGE AFTER EXTRACTION WITH ALIQUAT-336

A rapid method based on the extraction of neptunium(IV) by Aliquat-336 followed by its direct photometric determination in the organic phase employing xylenol orange is reported. Optinum conditions have been established for the extraction and determination of as little as 0.4 ppm of Np. The molar absorptivity of the red-coloured neptunium complex at 535 nm is 49535±361 1·mol-1·cm-1. Unlike the well-known absorptimetric method for estimating NP(IV) with Arsenazo III, this method tolerates many-fold excesses of fluoride, nitrite, nitrate, phosphote, oxalate as well as UO 2 2+, Pu4+, Zr4+, etc., which are some of the major contaminants associated with neptunium during its reprocessing. © 1979 Akadémiai Kiadó.