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Trace amount of uranyl (Ⅱ) has been determined spectrophotometrically by measuring the optical density of the light blue yellowish coloured solutions formed by reaction between the metal ion and nicotinohydroxamic acid (NHx) in presence of different secondary ligands in strong isoamyl alcohol alkaline medium. The absorption maxima for both aqueous and extracted systems measured at their respective optimum pH were found to be 360 and 559 ㎚ (DETA), 375 and 358 ㎚ (EDA), 369 and 362 ㎚ (piperidine), 354 and 341 ㎚ (pyridine) and 363 and 336 ㎚ (3 piperidine), 354 and 341 ㎚ (pyridine) and 363 and 336 ㎚ (3 -picoline), respectively at which Beer’s law was obeyed. Effect of pH, reagent concentration, order of addition of reagent, time, temperature and solvent media on the absorption spectra have also been studied. Among the different systems studied, the shortest concentration range of uranyl(Ⅱ) adhering to Beer’s Law was 2.4 - 10.5 ppm observed for UO₂(Ⅱ) - NHx - DETA system in aqueous medium and also for iso amyl alcohol(IAA) extracted UO₂- NHx - pyridine system was 2.4 - 7.8
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