双铝电极安培滴定法测定镀铬溶液中氟硅酸

DETERMINATION OF SILICOFLUORIC ACID IN CHROMIUN PLATING SOLUTION BY BIAMPEROMETRIC TITRATION

提出了以两支铝丝电极作为安培滴定法测定镀铬溶液中氟硅酸的指示电极系统,在pH3～5以硝酸钍溶液作为滴定剂,终点电流有明显的锯齿形转折。对溶液pH值的影响,外加电压的影响,有机溶剂的作用,干扰及其掩蔽等方面均作了详细的研究。所述条许下的滴定具有较好的选择性。可不经分离直接滴定镀铬溶液中的氟硅酸,方法简单、快速、准确。

Two Al wire elctrodes have been used for indicating the end point in the biamperometric titration of silicofluoric acid in chromiun plating solution with Th(NO_3)_4 solution as titrant. There is a sharp and abrupt current change at the end point. The influence nf pH.applteJ potential and the organic solvent used on the titration have been studied. The effect of interfering existing elements and their masking method has been investigated . Under optimal conditions the determination is highly selec ve . This method is rapid and accurate and has been applied to the direct determination of H_2SiF_6 in chremiun plating solutions.