| Abstract: | A very sensitive and selective adsorptive cathodic stripping procedure for trace measurement of uranium is presented. The method is based on adsorptive accumulation of the uranium‐pyromellitic acid (benzene‐1,2,4,5‐tetracarboxylic acid) complex onto a hanging mercury drop electrode, followed by reduction of the adsorbed species by voltammetric scan using differential pulse modulation. Influences of effective parameters such as pH, concentration of pyromellitic acid, accumulation potential and accumulation time on the sensitivity were studied. The peak current was proportional to the concentration of U(IV) up to 40 ng mL?1 with a limit of detection of 0.136 ng mL?1 with an accumulation time of 120 s. The range of linearity enhanced to 71.4 ng mL?1and the detection limit improved to 0.058 ng mL?1with accumulation times of 60 s and 300 s respectively. The relative standard deviation for 10 replicate determination of 4.76 ng mL?1 U(IV) was equal to 2.7%. The possible interference by major cations and anions are investigated. The method was applied to the determination of uranium in some analytical grade salts, seawater and in synthetic samples corresponding to some uranium alloys with satisfactory results. |
