蒸馏-催化极谱法测定复杂物料中微量砷

提出了用催化极谱法测定复杂物料中微量砷的含量。选择测定的溶液介质中含碲(Ⅳ)硫酸溶液5mL和150g.L-1碘化钾溶液5mL。仪器扫描速率为250mV.s-1,并采用二阶导数测定。试样(0.01～1.0g)用氯酸钾0.5g、氢氟酸5滴、硝酸5～10mL溶解,用蒸馏法分离其中的砷。砷的质量浓度在0.4mg·L-1以内与相应的峰电流呈线性关系。按此方法测定了12个矿样中砷含量,其测定值与已知值相符。方法的回收率在97%～100%之间,相对标准偏差(n=6)在2.3%～7.2%之间。

Catalytic Polarographic Determination of Micro-amount of Arsenic in Complex Materials with Separation by Distillation

It was reported that micro-amount of arsenic in complex materials were determined by catalytic polarography in testing solution containing 5 mL of Te(Ⅳ)-H2SO4 solution and 5 mL of 150 g·L-1 of KI solution.Anodic scanning at the rate of 250 mV·s-1 and 2nd derivative of the measured polarographic wave were adopted in the determination.The sample(0.01-1.0 g) was dissolved in KClO3(0.5 g),HF(5 drops) and HNO3(5-10 mL),and As ion was separated by distillation.Linear relationship between values of peak current and mass concentration of As was obtained in the range within 0.4 mg·L-1.Twelve samples of ores were analyzed by the proposed method for their arsenic contents,giving results consistent with the known values.Values of recovery and RSD′s(n=6) found were in the ranges of 97%-100% and 2.3%-7.2%.