Introduction

Cordycepin(3＇-deoxyadenosine)，an active constituent of Cordyceps sinensis and Cordyceps militaris，was the first nucleoside antibiotic separated from epiphyte(Cunningham et al.1950).It has extensive biological activities，such as anti-virus(Ahn et al.2000)，anti-fungus(Xu et al.2005)，anti-tumor(Choi et al.2011)，and immune enhancing functions(Zhou et al.2002).However，due to its low concentration，scarcity，and poor purification methods，commercial cordycepin is very expensive.The primary extraction methods for cordycepin involve microwave，ultrasound，enzymatic，and supercritical fluid extraction(Ling et al.2002；Wang et al.2005).Isolation methods have included ion exchange，activated charcoal，and silica gel column chromatography(Jiang et al.2000).These methods were characterized by low efficiency.More recently，alternative separations have been reported.D101 macroporous resin column chromatography was used to separate cordycepin from Cordyceps militaris(X.Hu et al.2012).Zhu et al.(2011)employed high-speed counter-current chromatography to purify cordycepin.Ni et al.(2009)isolated cordycepin with column chromatography.However，these methods were complicated，had low recoveries，and had low purification efficiency.

Molecularly imprinted polymers(MIP)are specific materials for separation and analysis.Molecularly imprinted polymers are formed by the copolymerization of a functional monomer and a template with a cross-linking agent.The template molecules are removed from the polymer，revealing complementary binding sites that may recognize the template from structurally similar compounds(S.G.Hu，Li，and He 2005).Molecularly imprinted polymers offer good specificity，simple preparation，and convenient regeneration，and hence they have been employed in various applications，including sample pretreatment and analysis of trace elements in the isolation of active pharmaceutical ingredients(Cirillo et al.2011；Bi，Tian，and Row 2012；He et al.2010).A molecularly imprinting polymer was prepared for the extraction of esculetin from ash bark(S.G.Hu et al.2005).The recovery of esculetin was 36%.Cheng and Yang(2006)applied a molecularly imprinted polymer to isolate puerarin from of Radix Puerariae，and obtained a higher recovery(83%)than a macroporous resin separation(Cheng and Yang 2006).(https://www.daowen.com)

In order to improve cordycepin purification，a molecularly imprinted polymer for this compound was prepared by a noncovalent bonding technique.The polymer was characterized and exhibited specific recognition for cordycepin.This molecularly imprinted polymer was shown to provide an efficient separation material for cordycepin.