Silica spheres

Six different kinds of silica gel were chosen as supports to prepare the Gossypol surface imprinted polymers. Silica spheres (0.5 μm average particle size) were obtained from Alfa Aesar (Shanghai, China); Silica spheres (5 μm average particle size) were obtained from Fuji Silysia Chemical Ltd. (Aichi, Japan); Silica spheres (60 μm average particle size) were obtained from Acchrom Technologies Co., Ltd. (Beijing, China); irregularly shaped silica gel (Thin layer chromatography, 10–40 μm), (200–300 meshes, 50–75 μm particle size) and (100–200 meshes, 75–150 μm particle size) were all purchased from Qingdao Haiyang Chemical Co., Ltd. (Qingdao, China). Gossypol was purchased from Sigma-Aldrich (Shanghai, China); (3-aminopropyl)triethoxysilane (APTES) (98%) was purchased from Alfa Aesar (Shanghai, China); tetraethoxysilane (TEOS) (98%), Quercetin (99%) and ellagic acid (98%) were purchased from Adamas (Shanghai, China); methanol, acetone, acetic acid, hydrochloric acid, and sodium hydroxide were all analytical grade, and were purchased from Tianjin Zhiyuan Chemical Co., Ltd. (Tianjin, China). Water was purified using a Millipore Milli-Q gradient system (Billeria, MA, USA) to high-performance liquid chromatography (HPLC) grade.