A new type of magnetic halloysite nanotubes molecularly imprinted polymer (MHNTs@MIP) based on halloysite nanotubes (HNTs) with embedded magnetic nanoparticles is prepared through surface imprinting technology, using 2,4-dichlorophenoxyacetic acid (2,4-D) as a template, 4-vinylpyridine as the monomer, divinylbenzene as cross-linking agents, and 2,2-azodiisobutyronitrile as initiator. MHNTs@MIP is applied as an adsorbent for sample pretreatment extraction followed by high-performance liquid chromatography detection of 2,4-D residue in water. Reprinted from Ref. [132]. Copyright 2014 Elsevier Ltd.