Magnetic molecularly imprinted polymer combined with solid-phase extraction for detection of kojic acid in cosmetic products

In this study, a new magnetic molecularly imprinted polymer Fe 3 O 4 @MIP is prepared via a surface molecularly imprinting technique; it is first applied as a magnetic solid phase extraction (MSPE) adsorbent for the selective and rapid extraction of kojic acid (KA) in cosmetic products. The as-prepared Fe 3 O 4 @MIP is characterized systematically, and is found to exhibit good monodispersity and high magnetic susceptibility in favor of fast separation. The adsorption capacity and equilibrium time of KA on the Fe 3 O 4 @MIP adsorbent are 314.0 mg/g and 30 min, respectively. In addition, the imprinting factor of Fe 3 O 4 @MIP is 2.09 for KA, which indicates that the prepared Fe 3 O 4 @MIP exhibits good selectivity for KA. Under the optimum experimental conditions, the KA in cosmetic products was successfully extracted with Fe 3 O 4 @MIP adsorbent and determined by ultraviolet–visible (UV–vis) spectrophotometry. Validation experiment shows that the developed method presents good linearity (50–500,000 μg/L), satisfactory precision (RSD, 2.5–4.6 %), and high recovery (92.4–104.6 %). The limit of detection (LOD) is 21.4 μg/L, and the enrichment factor is 299. These results suggest that this MSPE method coupled with UV–vis spectrophotometry holds great potential for efficient sample pretreatment and target molecule determination in real samples.