In the present study, the use of Fe3O4@PDA NPs as d-SPE adsorbents to simultaneously adsorb and preconcentrate four water-soluble colorants in beverage samples was developed. The colorant capture and release were pH-sensitive due to the zwitterionic character of PDA polymers. Excellent extraction performances for colorants were obtained owing to the large specific surface area of the nanomaterials and the multiple interactions between PDA and colorants. Due to the magnetic property, the operation was convenient and rapid for d-SPE procedure. The proposed magnetic D-SPE-HPLC method exhibits high sensitivity, satisfactory spiked recovery and good repeatability for the analysis of colorants in real samples.