Solution polymerized styrene-butadiene rubber ( S-SBR ) was fractionated by repeated precipitation method, using redistilled toluene as solvent and ethyl alcohol as precipitant.
本工作用甲苯作溶剂，乙醇作沉淀剂，用沉淀分级法，对溶聚丁苯橡胶（S-SBR）进行了分级。
After ethanol precipitation, OPC was separated by ethyl acetate-ligroin system. Content of OPC was determined by normal butyl alcohol-hydrochloric acid method at 546 nm to be over 90%.
提取物经醇沉后，用石油醚沉淀法分离低聚原花青素，产物经正丁醇-盐酸法显色，比色法测定质量含量可达90%以上。
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