SEPARATION AND DETERMINATION OF COPPER AND ZINC BY ION CHROMATOGRAPHYUSING 2-(2-BENZOXAZOLYLAZO)-1-NAPHTHOL AS A POSTCOLUMN DERIVATIZATIONREAGENT

An ion chromatographic method using postcolumn derivatization with 2-( 2-benzoxazolylazo)-1-naphthol(alpha-BOAN) in a nonionic surfactant sol ution of Brij35 was established for the separation and determination o f copper(II) and zinc(II). The optimum conditions for determining the elements were: an eluent containing 0.25 mol dm(-3) lactic acid (pH 3. 1) at a flow rate of 1 mi min(-1); for postcolumn derivatization, a 2 x 10(-4) mol dm(-3) alpha-BOAN solution containing 4% (v/v) dioxane, 4 %(w/v) Brij35 and sodium tetraborate at a flow rate of 0.3 mi min(-1); pH at the drain of 3.3 +/- 0.1; analytical column, a Shim-pack IC-Cl (5.0 mm i.d x 150 mm); oven temperature of 40 degrees C; an injection volume of 0.02 mi; and detection at 565 nm. A linear relationship was observed between the peak hight and the amount of elements within rang es of 80 similar to 240 and 400 similar to 2000 ppb for copper and zin c, respectively. The relative standard deviations for the measurements (n = 7) of 120 ppb Cu and 800 ppb Zn were 2.2 and 2.0%, respectively; the detection limits of 16 ppb Cu and 195 ppb Zn (S/N = 3) were obtai ned. The present method was applied to the separation and determinatio n of copper(II) and zinc(II) in the Rice Flour (NIST SRM1568a) and Bov ine Liver (NIST SRM1577b) with satisfactory results.