ジンコンによる鋳鉄中亜鉛の光度定量法

抄録

The fundamental conditions for photometric determination of zinc using zincon (2-carboxy-2′-hydroxy-5′-sulfoformazylbenzene) have been investigated and applied to the analysis of cast iron. Zinc-zincon complex shows high absorbancy at 615 mμ over pH 8.5∼9.5, and is stable at least for 1 hour. However the stability of absorbancy varies with the maker of zincon. It obeys Beer’s law up to 200γ of zinc in 50 mL for 1 cm cell. Preliminary separation of zinc from large amounts of iron etc. is made by extraction with dithizone in benzene from citrate solution of pH about 8.3 and following back extraction with dilute hydrochloric acid solution. The proposed method is suitable for determining 0.002∼0.04% of zinc in cast iron, when carried out without great care which is necessary in the dithizone photometric method.