饲料级硫酸锰中微量铅镉的极谱法连续测定

Continuous Measurement of Plumbum and Cadmium by Polarographic Analysis in Feed Grade Manganese Sulfate

在氨基乙酸-氯化铵-盐酸羟胺底液中，Pb（Ⅱ）于-0．55V（us，SCE），Cd（Ⅱ）（us，SCE）于-0．74V产生灵敏的吸附波，铅镉的浓度在0．02～5μg∥mL范围内与波高呈线性关系，大量的锰、硫酸根离子使铅镉的波高下降，用标准加入法消除基体的干扰。试样经水直接溶解后，在上述条件下进行测定，铅标准回收率：96．6％～115．O％，相对标准偏差：8．O％。～18．6％；镉标准回收率：91．8％～106．1％，相对标准偏差：15．2％～19．5％。适用于饲料级硫酸锰中铅、镉含量〉0．5μg∥g试样的测定。

In base solution of aminoacetic acid-ammonium chloride-hydroxyamine hydrochloride, Pb^2＋ and Cd^2＋ create sensitive adsorption wave at - 0.53 V（vs. SCE） and - 0.74 V （vs. SCE） respectively. The height is linear with concentration of plumbum/cadmium in the rang of 0.02 ～5 μg/mL. High concentration of manganese ions and sulfate ions might decrease the wave height, such disturbance of base solution is eliminated by standard addi- tion method. Being dissolved in water, samples are continuously measured under above mentioned conditions. Recovery rate of plumbum ranges from 96.6% ～115%, relative standard derivation ranges from 8.0% to 18.6% ; recovery rate of cadmium ranges from 91.8% ～106.1%, relative standard derivation ranges from 15.2% to 19.5 %. Such a method is applicable for feed grade manganese sulfate, when concentration of plum bum cadmium is higher than 〉 0.5 μg/g.