Spectrophotometric determination of zinc in salt with Zn~(2+)-phen-titan yellow system

In ammonium acetate buffer solution at pH 7.0,Zn2+ reacts with phen and titan yellow(TY) to form a stable ion-association complex [Zn(phen)3]·2,which leads to the enhancement of absorbence.Based on this fact,a new spectrophotometric method for the determination of zinc was proposed.The maximum absorption wavelength of the ion-association complex locates at 464 nm.The Beer's law was obeyed in the range of 0~1.4 μg/mL for Zn(II).The apparent molar absorption coefficient was 2.52×104 L/mol·cm.The detection limit was 27.3 μg/L.The method has been applied to the determination of zinc in health balance salt and fortified nutrient salt with zinc.The relative standard deviation was 1.05%~1.23%(n = 5),and the average recovery was 98.9%~100.3%.