Water-compatible micron-sized monodisperse molecularly imprinted beads for selective extraction of five iridoid glycosides from Cornus officinalis fructus

An efficient, accurate and sensitive method for the determination of five iridoid glycosides (IGs) in Cornus officinalis fructus using molecularly imprinted solid phase extraction (MISPE) coupled with high performance liquid chromatography (HPLC) has been developed. Water-compatible molecularly imprinted beads (MIBs) were synthesized by precipitation polymerization, using alkenyl glycosides glucose as the hydrophilic functional monomer. Scanning electron microscopy showed that the MIBs had a narrow particle size distribution, with diameters in the range 7.5-9.3μm. The special molecular recognition by the MIBs of IGs in aqueous media was verified by static adsorption, kinetic adsorption, and selectivity experiments. The newly prepared MIBs were used as sorbents in solid phase extraction (SPE) for the selective recognition of five IGs (loganin, morroniside, loganic acid, 7-O-ethyl-morroniside and 7-O-methyl morroniside) in Cornus officinalis fructus. When optimized, the MISPE-HPLC method had good linearity (0.02-100mgg^-1), with correlation coefficient (R)≥0.994. Recoveries at three spiked levels were in the range 80.0%-94.0%. Because of its excellent specificity and hydrophilicity, SPE based on monodisperse MIBs provides a promising pretreatment strategy for the analysis of active components in Natural Products, especially for the quality control of traditional Chinese medicines.