7497
Here , a novel bovine monocyte chemotactic factor ( boMCF - 1 ) was isolated from commercial bovine serum by a four step purification procedure including adsorption to silicic acid , heparin affinity and cation - exchange chromatography and reversed phase HPLC .
 Chemical: silicic acid
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: silicic acid