采用氟离子选择电极法测定了稀土-镁中间合金中的氟含量,稀土和镁基体对氟的测定干扰严重,以氢氧化钠将基体沉淀分离后,过量氢氧化钠造成的二次干扰需以标准加入法消除。试验确定的最终条件为,以30%氢氧化钠将基体沉淀分离,控制溶液pH值为5～6,以TISAB缓冲溶液调节溶液离子强度,由标准曲线确定一定温度下的斜率S,不使用格氏作图纸,以单点标加法测定并计算合金样品中氟的含量。 Fluorine ion selective electrode method was used to determine the content of fluorine in the rare earth-magnesium master alloy. The rare earth and magnesium matrix had a serious interference with the determination of fluorine. After sodium hydroxide precipitated the matrix, the second interference caused by excessive sodium hydroxide needed Standard join law to eliminate. The final conditions determined experimentally, the matrix precipitation with 30% sodium hydroxide separation, the control solution pH value of 5 to 6, TISAB buffer solution to adjust the ionic strength of the solution, the standard curve to determine the temperature at a certain slope S, ’S drawings, measured by single-point addition and calculation of alloy samples of fluorine content.