钙镁试剂-示波计时电位法快速测定天然水中不同形态铝

DETERMINATION OF ALUMINUM FRACTIONS IN NATURAL WATERS BY A.C.OSCILLOPOLAROGRAPHY USING CALMAGITE

采用钙镁试剂 (CLG) 示波计时电位法 ,分别在中性和碱性条件下直接检测天然水中的无机单核铝 [Ali]和总单核铝 [Ala]浓度 .并用该法测定了酸消化水样中的总铝 [AlT],由 [Ala]-[Ali]间接得到有机单核铝 [Alo],[AlT]-[Ala]得到酸溶态铝 [Alr],从而实现了水中五种Al形态的电化学测定 .实验结果表明 :在pH9 0的 0 5mol·1 - 1KCl+ 0 1mol·1 - 1Na2 B4 O7缓冲溶液中 ,CLG切口为Ep1=-0 75V ,加入铝后出现新切口 ,Ep2 =-0 90V ,检测线性范围为 8× 1 0 - 6— 4× 1 0 - 5mol·1 - 1,检测下限为 6× 1 0 - 7mol·1 - 1,在 3× 1 0 - 5mol·1 - 1Al时 ,相对标准偏差为 4 8% (n =1 0 ) .在中性条件下测定的是无机单核铝 ,而在碱性条件下则是总单核铝 (包括无机单核铝和有机单核铝两部分 ) .

Fast determination of five fractions of aluminum in natural waters respectively under neutral and alkalized conditions by a. c oscillopolargraphy in the presence of calmagite(CLG)is presented in this paper. In 0.5 mol·1 -1KCl+0.1 mol·1 -1 Na 2B 4O 7 alkaline solution (pH9.0),3.5×10 -4mol·1 -1CLG yields an incision at the potential of-0.75V. When Al is added, a new incision appears at-0.90V. The incision depth of Al-CLG complex is linear with the Al concentration added. The linear range is 8×10 -6-4×10 -5mol·1 -1and the detection limit is 6×10 -7 mol·1 -1.The relative standard deviation (n=10,3×10 -5mol·1 -1Al)is 4.8%. The Al concentration detec- ted in the alkaline condition is proved to be the totalmonomeric Al a(including inorganic monomeric Al i and organic monomeric Al o). However, in the neutral condition, the method can only detect the inorganic monomeric Al i.