Solid-phase extraction of ultratrace uranium(VI) in natural waters using octadecyl silica membrane disks modified by tri-n-octylphosphine oxide and its spectrophotometric determination with dibenzoylmethane

A simple and reliable method for rapid extraction and determination of uran ium in natural waters using octadecyl-bonded silica membrane disks modified with tri-n-octylphosphine oxide (TOPO) and spectrophotometry with dibenzoy lmethane is presented, Extraction efficiency and the influence of sample ma trix, type, and optimum amount of extractant, flow rates, and type and mini mum amount of organic eluent were evaluated, The maximal capacity of the me mbrane disks modified by 50 mg of TOPO was found to be 4033 mu g of uranium . The limit of detection of the proposed method is 100 ng/1000 mt. The meth od was applied to the extraction and determination of uranium in natural wa ters.