Polystyrene-polyricinoleic acid copolymer containing silver nano particles (AgPSrici) was synthesized and used in separation of molybdenum from different aqueous and foodstuff samples during a dispersive-mu-solid phase extraction approach. The synthesized nano particles were verified using Fourier transform infrared spectroscopy. An electrothermal atomic absorption spectrometry has been used for measurement of the studied ions. AgPSrici amount pH, sample volume, elution solvent kind, and the time of extraction were the effective parameters that were optimized by one-variable-at-one-time method. Analytical data of the method was calculated and limit of detection, relative standard deviation, limit of quantification were 0.022 mu g L-1, 2.9%, 150, and 0.066 mu g L-1, respectively. The synthesized adsorption capacity was obtained 170 mg g(-1). Accuracy of the method was studied by performing the method on certified reference materials and the presence of different interfering ions was studied. Molybdenum content of different water and foodstuffs was determined by the introduced method.