离子选择电极电位法快速测定腐植酸肥料中氯离子含量的研究

Rapid Determination of Chloride Ion in Humic Acid Fertilizer by Ion Selective Electrode Potential Method

建立了一种快速准确测定腐植酸肥料中氯离子的电位法。采用氯离子选择电极为工作电极,带KNO_3盐桥的Ag/AgCl为参比电极,pH=9,0.1 mol/L的H_2PO_4^-～HPO_4^(2-)溶液为总离子强度调节缓冲剂,室温下测量了腐植酸肥料中氯离子含量。结果显示,氯离子选择电极响应电位与腐植酸肥料中氯离子浓度在1.0×10^(-4)～1.0×10~0 mol/L范围内呈良好的线性关系,线性回归方程为E=-9.188+54.91pC,回归系数R^2=0.9975;平均加标回收率为99.12%;重现性试验,平均相对标准偏差RSD=0.26%(n=10)。该方法线性范围宽,检测限低,选择性好,准确度高,不受腐植酸颜色影响,测定快速简便。

A rapid and accurate method for the determination of chloride ions in humic acid fertilizer was developed.Chloride ion selective electrode using as working electrode,the Ag/AgClwith KNO3salt bridge as reference electrode,and H2PO4^-~HPO4^2-solution with pH=9,0.1mol/L as total ion strength adjusting buffer,the content of chlorine ion in humic acid fertilizer was measured at room temperature.The results showed that the chloride ion selective electrode response potential showed a good linear relationship with the chloride ion concentration in humic acid fertilizer in the range of 1.0×10^-4~1.0×10^0mol/L,and the linear regression equation was E=-9.188+54.91pC,and the regression coefficient R^2=0.9975,average marking recovery was 99.12%;for reproducibility tests,mean RSD=0.26%(n=10).The method has the advantages of wide linear range,low detection limit,good selectivity and high accuracy,simple and rapid operation,especially no affected by color ofhumic acid.