A novel and versatile adsorbent based on 1-octadecylimidazolium ionic liquid modified magnetic nanoparticles (Fe₃O₄@SiO₂@ImC18) possessing of both magnetic property and excellent adsorption ability was successfully synthesized. Twelve compounds from four kinds of substances (alkylbenzenes, PAHs, flavonoids and organic acids) were chosen as probe molecules to evaluate adsorption properties of the new adsorbent. A series of adsorption experiments were conducted and results indicated both synergism and competition effects were existed and multiple interactions took place during adsorption process. After considerable acquaintances with the adsorbent, it was successfully applied for real samples analysis of honey and cinnamon. Three flavonoid compounds of myricetin, quercetin and luteolin from honey and cinnamic acid from cinnamon were all detected and quantified. Meanwhile, it reached 280-fold concentration reduction of interferent during the extraction of cinnamic acid from cinnamon. The recoveries were in the range of 85.4–94.8% with relative standard deviations (n = 3) of 2.5–5.6%.The current study not only provided a strategy to evaluate new adsorbent, but also demonstrated the novel Fe₃O₄@SiO₂@ImC18 material was reliable, accurate and suitable for sample pretreatment in pharmaceutical and food chemistry.