催化极谱法测定土壤和植物中微量钴

Catalytic Polarographic Determination of Trace Cobalt in Soil and Plant

用阶梯扫描伏安法研究了钴—亚硝酸盐—乙二胺体系在静汞电极上的催化波,用以测定土壤和植物中的微量钴。实验证明,钴浓度在0.001～0.3ppm范围内与峰电流呈良好的线性关系,检出下限为0.5ppb。土壤和植物中相对钴大量存在的Fe,Mn,Mg,Zn和Cr等干扰测定。用甘油掩蔽Zn,用双硫腙—CCl_4萃取钴,能有效地消除上述元素的干扰。测定的相对标准误差小于8％,试样回收率在92～109％之内。此方法灵敏可靠。

The polarographic catalytic wave of Cobalt in Ethylene Diamine-Nitrite solution has been applied to determine trace Cobalt in soil and plant by staircase voltammetry on static mercury drop electrode. The experiments show that the linear relationship holds between peak current and Cobalt concentration ranging from 0. 001 to 0. 3ppm. The limit of detection for Co is 0. 5 ppb. The interference of coexistent elementsFe, Mg, Mn, Zn and Cr in soil and plant has been removed effectively by covering-extraction. The relative standard error is less than 8% and the rate of recovery is 92~109%. This method is sensitive and reliable.