FLOW-INJECTION SPECTROPHOTOMETRIC DETERMINATION OF URANIUM WITH IN-VALVE ION-EXCHANGE COLUMN PRECONCENTRATION AND SEPARATION

An in-valve column containing Duolite C-225(H) resin for preconcentration and separation flow injection determination of uranium is described. Uranyl ions loaded on the column were eluted with 1 mol 1(-1) HCl and mixed with a stream of buffer and masking solution [triethanolamine (1 mol 1(-1)) and 1,2-cyclohexanediaminetetraacetic acid (0.7% m/v)]. After passing through a glass bead column the complex product was continuously monitored at 530 nm. Calibration by time (or volume) using a single standard was performed up to 7 mu g of U. The detection limit (3 sigma) and relative standard deviation were 0.27 mu g of U and 2.1% (for 2 mu g; n = 12), respectively. Interferences of some ions were studied. Applications to the determination of uranium in rock and water samples are described.