Abstract: A method based on monolithic molecularly imprinted polymer enrichment combining with high performance liquid chromatography (mMIP-HPLC) detection was developed for the selective determination of trace cytokinins (CTKs) in plant samples. Monolithic molecularly imprinted polymer (mMIP) column was prepared in stainless steel tube by using kinetin as the template, methacrylic acid (MAA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker, and toluene-dodecanol as the porogenic solvents. Compared with non-imprinted polymer (NIP) monolith, the prepared mMIP exhibited selective separation ability, good reproducibility and reusability, and high extraction efficiency in the separation and enrichment of the four CTKs. Under the optimized experimental conditions, mean recoveries were 91.9%、80.0%、87.5% and 50.2% for kinetin (K), kinetin glucoside (KR), trans-zeatin (tZ) and meta-topolin (mT), respectively, with the corresponding RSDs less than 11.8%. The proposed mMIP-HPLC method was successfully applied in the separation and determination of the four cytokinins in different plant samples.

Key words: cytokinins, high performance liquid chromatography (HPLC), monolithic molecularly imprinted column, plants, sample preparation