SPECIFIC METHOD FOR SPECTROPHOTOMETRIC DETERMINATION OF MOLYBDENUM INSOIL

A new, simple and specific spectrophotometric method for the determina tion of Mo in the soil extracts is described. Mo(VI) is reduced to Mo( V) with sodium borohydride and allowed to react with SCN- ions in the presence of cationic and neutral surfactants e.g. CPC and TX-100 in th e acidic aqueous solution. The molar absorptivity of the complex in bo th the aqueous, and toluene solutions is (2.30) x 10(4) 1 mol(-1) cm(- 1) at absorption maximum, 460 nm. The extraction-procedure preconcentr ated Mo at least 3-folds, the detection limit is 125 ng Mo/g soil. The analytical variables of the method have been optimised and compositio n of the complex is proposed. None of the tested foreign ion interfere d in the determination of Mo up to a large amount. An attempt for the removal of Fe-interference in the determination of Mo in soil extract has been described. The method has been found to be satisfactorily app licable for the determination of Mo in hot water leachates and acid di gested soil solutions at lower ppm levels.