催化极谱法测定人造奶油中的镍

Determination of Nickel in Butterine by Catalytic Polarography

在pH=8.2丁二酮肟—氨水-氯化铵—亚硝酸钠体系中,镍具有一灵敏的极谱波,其二阶导数峰电位为-0.97V(vs.SCE),峰电流与镍离子浓度在0.00603mg/L^0.1809mg/L范围内呈线性关系,线性方程ip"=738.0+6.591×104c(相关系数为r=0.9979)。比较了人造奶油的预处理方法,测定了人造奶油中的镍,加标回收的最大相对标准偏差为5.2%。

Nickel has a sensitive and stable catalytic polarographic wave at the supporting electrolyte solution of dimethyl - glyoxime, sodium nitrite, and ammonia - dammonium chloride with pH = 8.2. Its second - order derivative peak potential is - 0.97V （vs SCE）. The peak current is proportional to the concentration of nickel over the range from 0.008 44 mg/L to 0. 180 9 mg/L. The linear regression equation is ip＂ （ n.A-/s^2 ） = 738.0 ＋ 6.591×10^4c, with the correlation coefficient 0. 997 9. The pretreatment methods of butterine were compared for the determination of nickel in butterine. The experimental results show that the ashing method is superior to extraction method. The content of nickel in butterine was determinated. The maximum relative standard deviation in recovery of standard reference is 5.2%.