Spectrophotometric measurement of Cu(DDTC)2 for the simultaneous determination of zinc and copper

► Zinc measurement based on the quantitative displacement of zinc from Zn(DDTC)2 with excess copper(II). ► Both copper and zinc were measured in the range 0.2-14 μg mL−1 and 0.2-12 μg mL−1, respectively. ► The molar absorptivity (ε), 2.86 × 105 mol−1 L cm−1. ► Method were found to be in excellent agreement with those results (biological sample) obtained by ICP-MS.