Application of bifunctional monomer surface MIP with MOFs nanocomposite for efficient trapping and analysis of luteolin in compound Anoectochilus roxburghii (Wall.) Lindl. oral liquid

Luteolin is one of the bioactive components from the compound Anoectochilus roxburghii (Wall.) Lindl. oral liquid (CAROL), which was reported to have excellent hepatoprotective and anti-inflammatory activities. However, the enrichment and quantitation of luteolin from CAROL is challenging due to the low content and complex aqueous matrix. In this study, a bifunctional monomer surface molecularly imprinted polymer (MIP) with metal–organic frameworks (MOFs) as cores was prepared for the selective adsorption of luteolin from the aqueous system CAROL. Compared with conventional MIPs, this unique nanocomposite adsorbent (MOF@MIPs) has the advantages of short kinetic equilibrium time, good selectivity, and high adsorption capacity in aqueous solution. The theoretical maximum adsorption capacity of MOF@MIPs for luteolin was 36.99   mg/g. After adsorption enrichment of luteolin from CAROL using MOF@MIPs, liquid chromatography–tandem mass spectrometry was applied to analyze the target. The corresponding linearity range for analyte was 10–6000   ng/mL with good linearity (R 2 =0.9992), and the added recoveries varied from 85.70% to 99.25%. The present method has been successfully employed for the analysis of luteolin in five different batches of CAROL. Notably, we found no significant difference in the content of luteolin between these batches, which proved that the composition was stable between batches. The novel structure MIPs are suitable for the specific recognition of template molecules in aqueous solution. Therefore, this study provides a technical reference for the special identification and determination of trace components in complex samples, while the novel MOF@MIP nanocomposite can also provide valuable references for the extraction and purification methods of specific substances in traditional Chinese medicine and expand the application environment of MIPs material.