The use of Zincon for preconcentration and determination of Zinc by flame atomic absorption spectrometry

Abstract

A method for the determination of zinc using zincon as an enrichment agent and flame atomic absorption spectrometry was developed. The system consists of a glass column containing 200 mg of Dowex 1X8 resin modified with 1% (w/w) of zincon. The recovery of the metal was quantitative at pH 7.0 to 8.0 with the use of a potassium dihydrogen-phosphate/sodium hydroxide buffer solution. The colored complex was eluted from the column with 10.0 mL of a 0.1 mol L⁻¹ HNO₃ solution. Using these conditions an enrichment factor of 25 and at least 15 re-utilizations of the column were possible. The limit of determination was 1.7 μg L⁻¹ and a relative standard deviation of 1.2% was obtained, calculated from 10 measurements. The foreign ions effect was studied and the system showed no significant interferences. The accuracy was ascertained by using certified reference material and the results obtained were in agreement with the certified values. The proposed method was successfully used for the determination of zinc in fruit juices.