Facile spectrophotometric determination of cerium using malachite green –iodide system in geological and environmental samples

A simple and highly sensitive method is proposed for determination of trace amount of cerium. New method involves bleaching of greenish colour dye-malachite green, by the action of iodine, which is released by reaction between potassium iodide and cerium (IV) in acidic medium. Beer's law is obeyed over concentration range of 0.6 to 4.6 μg cerium (IV) in final volume of 25 ml (0.024-0.184 ppm). Molar absorptivity and Sandell's sensitivity were found to be 1.36 x 10 5 l mol -1 cm -1 and 0.002 μg cm -2 , respectively. New method has been successf ully applied for determination of cerium in silicate rocks, high purity rare earth oxides, soil, plant tissue and natural water samples.