CHAPTER 47 - Zinc

Abstract

The ease, simplicity, and freedom from interference that characterize the determination of zinc by atomic absorption spectroscopy (AAS) is in direct contrast to the lengthy and difficult determination by spectrophotometry method, for which a careful separation from interfering elements is required. The zinc line at 213.9 nm is of more than adequate sensitivity in an air–acetylene flame. The determination of zinc by AAS method can be combined with the determination of a number of other elements of adequate sensitivity by AAS. The calibration curve for zinc is slightly convex towards the concentration axis. This chapter discusses the spectrophotometric determination of zinc following ion-exchange separation. Zincon is a red organic reagent that forms a blue complex with zinc in alkaline solution. Many ions interfere with the determination of zinc, including aluminum, beryllium, bismuth, cadmium, cobalt, chromium (III), copper, iron (III), manganese, mercury, molybdenum (VI), nickel, and titanium, which all react with the reagent, and these must be separated before the zinc complex is formed. Anion-exchange separation can conveniently be used for this.