极谱法测定铝合金中锆

利用锆（Ⅳ）在盐酸介质中能与水杨基荧光酮（SAF）形成非电化学活性络合物的性质，建立了以测定水扬基荧光酮的还原峰电流而间接测定锆的极谱新方法。该方法最佳底液组成为：0.24 mol/L的盐酸，8.0×10-5 mol / L的水杨基荧光酮乙醇溶液，2.4 mg/L的聚乙二醇（20 000）溶液。Zr（Ⅳ）在-0.68 V（vs.SCE）左右有一尖锐的极谱峰，峰电流与Zr（Ⅳ）浓度在0～840μg /L范围内成线性关系，检出限为0.004 2 μg /L。将该法与微波消解的溶样方法相结合测定了铝锆合金标准样品中锆，测定结果与认定值相符。用单扫描极谱法研究了锆的极谱行为，证明了电极反应物为水杨基荧光酮，极谱波为不可逆还原吸附波。本方法适用于铝锆合金中含量≤10%的锆测定。

Determination of zirconium in aluminium alloy by polarography

On the basis of the property whose zirconium （Ⅳ） could form non-electrochemical active complex with salicyl fluorone （SAF） in hydrochloric acid medium, a new indirect determination method of zirconium by measuring the reducing peak current of SAF was established. The optimal base solution of this method was as follows: 0.24 mol/L hydrochloric acid, 8.0×10-5 mol / L SAF ethanol solution and 2.4 mg/L polyethylene glycol-20000 solution. Zr（Ⅳ） showed a sharp polarographic peak near -0.68 V （vs.SCE）. The peak current was linear to the concentration of Zr（Ⅳ） in the range of 0-840 μg /L, and the detection limit was 0.004 2 μg /L. This method was combined with the sample preparation by microwave digestion, and applied to the determination of zirconium in aluminium zirconium alloy standard sample. The results were consistent with the certified values. The polarographic behaviour of zirconium was studied by single scanning polarography. It proved that the electrode reactant was SAF, and the polarographic wave was irreversible absorptive reducing wave. The proposed method was applicable for the determination of zirconium （≤10 %） in aluminium zirconium alloy.