本文报告了一个微量测定有机化合物中氟的新方法。本法终点敏锐、操作简便,适于常规分析。样品以Schniger氧瓶法分解,分解产物用稀NaOH溶液吸收。在酸性溶液中将F~-沉淀为CeF_3后,过量Ce(Ⅲ)在适量乙醇存在下,不经过滤,用六亚甲基四胺调节pH=5.6±0.4,以二甲酚橙-亚甲蓝为指示剂,用EDTA溶液滴定。单独测定一次约半小时,绝对误差±0.3％。 This article reports a new method for the trace determination of fluorine in organic compounds. The method is sharp at the end, easy to operate and suitable for routine analysis. Samples were disassembled using the Schniger oxygen bottle method and the decomposition products were absorbed with dilute NaOH solution. After precipitation of F ~ - into CeF_3 in acidic solution, excess Ce (Ⅲ) was filtered without pH and adjusted with hexamethylenetetramine (pH = 5.6 ± 0.4) Blue as an indicator titrated with EDTA solution. Measured alone about half an hour, the absolute error of ± 0.3%.