痕量Au、Bi和Cd的萃取浮选及原子吸收光谱法测定

FLOATATION-SPECTROPHOTOMETRIC DETERMINATION OF Au,Bi AND Cd

浮选法分离痕量金属离子,由于灵敏度高、选择性强已得到广泛应用。本文利用浮选法使Au3+、Bi3+和Cd2+同KBr反应生成的络合阴离子与碱性染料罗丹明B（RB）生成既疏水又疏有机溶剂的三元离子缔合物,后者经甲苯浮选分出,用二甲基甲酰胺（DMF）溶解后,可用原子吸收法测定Au、Bi和Cd的含量。本方法用于海水,锌片和矿样中上述三种元素的微量测定,可提高检测灵敏度,而且K、Na、Ca、Mg等共存离子不生干扰。具体实验方法如下:

Bromide complexes of Au(Ⅲ), Bi(Ⅲ) and Cd(Ⅱ) ions form associates with rhodamineB.The associated substances can be separated by floatation and determined for Au, Bi andCd by air-acetylene flame atomic absorption-spectrophotometry. The optimum conditions for.the determination are described. The floating recovery ratio is greater than 90%. By thismethod, it is possible to determine trace amount of Au, Bi and Cd in sea water, pure zincplates and minerals. Co^(2+), Ni^(2+), Ca^(2+), Al^(+3),Fe^(3+), Mg^(2+), Mn^(2+), Cr^(3+),K^+ and Zn^(2+) etc.do not interfere the determination. The detection Iimit was found to be 25ng/mL for Au,60ng/mL (for Bi) and Cd 4.5ng mL (for Cd) respectively.