Molecularly imprinted solid-phase extraction of (−)-ephedrine from Chinese Ephedra

Method of molecularly imprinted solid phase extraction (MISPE) of (−)-ephedrine from Chinese Ephedra has been developed in the research. The molecularly imprinted polymer (MIP) with good selectivity and affinity for (−)-ephedrine was synthesized with (−)-ephedrine as the template, methacrylic acid as the functional monomer. The washing and elution conditions in MISPE were selected and optimized for efficient analyte extraction and sample clean-up. A clean analytical HPLC base line of ephedra extract was obtained after MISPE, which indicated that the sample pre-treatment was efficient. Good recovery and precision were obtained in the assessment for the MISPE–HPLC procedure, which demonstrated it is a reliable method and can be used for the determination of (−)-ephedrine in herbal ephedra.