This study utilized reduced graphene oxide magnetic nanoparticles Fe₃O₄/rGO-MNP to preconcentrate two alkyl phenols, two organochlorine pesticides and one organophosphate pesticide from water and baby food samples for the determination by gas chromatography flame ionization detector (GC-FID). Parameters of the micro-solid phase extraction (μ-SPE) were fully optimized to boost the measurement signals of the analytes. Optimum extraction conditions were applied to aqueous standard solutions to validate the method. The limit of detection ranged between 0.48 and 2.4 μg/L, recording about 60–100 folds enhancement in detection power when compared directly with the detection limits of the instrument before preconcentration. The optimum method was applied to aqueous samples and spiked recovery tests produced satisfactory results. The baby food sample was treated with the QuEChERS standard method before applying the μ-SPE method. Matrix matching was used to overcome matrix interference to obtain approximately 1.0 % recovery results for all analytes spiked at different concentrations.