氟离子选择性电极-标准加入法测定硫酸锌溶液中氟

Standard addition method for the determination of fluoride in zinc sulfate solution by fluoride ion-selective electrode

研究了在总离子强度调节缓冲液（TISAB）体系中采用氟离子选择性电极标准加入法测定复杂硫酸锌体系中氟的新方法.结果表明：溶液中氟离子的质量浓度在0.5～38.0 mg/L范围内,氟离子质量浓度的负对数与相应电极电位（E）存在良好线性关系,线性相关系数r=0.999 8.根据加标前后电位的变化,可直接测定并计算出硫酸锌溶液中的氟含量.相对于2mg/L F,2.0×10^4倍Zn2＋,1.0×10^3倍Fe2＋,1.2×10^3倍Al3＋,1.0×10^3倍Mg2＋,1.1×10^3倍Ca2＋不干扰测定.方法已成功应用于复杂硫酸锌体系中氟的测定,检出限为0.023mg/L,相对标准偏差（RSD）≤2.0％,氟的加标回收率在99％～102％之间,测定值与离子色谱法的测定值一致.

A new method for the determination of fluoride ion in complex zinc sulfate solution system is studied in the total ionic strength adjustment buffer （TISAB） liquid system by standard addition method with a fluoride ion-selective electrode. The results show that there is a good linear relationship between the negative logarithm of fluoride ion concentration and the corresponding measured electrode potential when the fluoride ion mass concentration is between 0.5 mg/L and 38.0 mg/L,with correlation coefficient of r=0. 999 8. AccOrding to the change of electrode potential after adding standard solution, fluoride ion concentration in zinc sulfate solution can be measured and calculated directly. For 2 mg/L F- , 2.0X 10; times Zn2＋ , 1.0×10^3 times Fe2＋ , 1.2×10^3 times AP＋ , 1.0×10^3 times Mg2＋ and 1.1×10^3 times Ca2＋ don＇t interfere in the determination. The proposed method＇has been applied successfully to determine fluoride ion in complex zinc sulfate solution system. The limit of detection is 0. 023 mg/L. The relative standard deviation（RSD） are less than or equal to 2.0 ;, and the addition standard recovery of fluoride ion is in the range of 99%-102%. The results of this method are consistent with those of ion chromatography.