In this study Fe₃O₄@hydroxide and Fe₃O₄@oxide nanoparticles were investigated for the magnetic headspace adsorptive microextraction for the first time. Fe₃O₄-based composite magnetic nanoparticles were used for adsorption of volatile phenols as model analytes from baby food samples. The effect of nanoparticle composition on adsorption behaviors of phenols was studied. The results showed that the synthesized Fe₃O₄@Cr(OH)₃nanoparticles provided the most effective headspace adsorptive microextraction of phenols. A novel sample preparation procedure for the determination of phenols in food samples by high performance liquid chromatography with fluorescence detection was developed. A linear calibration range of 0.5-2500 μg kg⁻¹was obtained with correlation coefficients in the range of 0.996-0.998. The LOD, calculated from a blank test, based on 3σ, was 0.2 μg kg⁻¹. The repeatability of the proposed method was evaluated at 0.5 and 2000 μg kg⁻¹spiking levels, and the coefficients of variation ranged between 1 and 8% (n= 4). The developed procedure provided phenol separation from samples with recovery from 90 to 118%.