Determination of the Heavy Metals Chromium and Copper in Water by Reflectometry

Contents of the heavy metals chromium and copper in water were determined by reflectometry. For determination of chromium(Ⅵ), the sample was digested with H2SO4 and mixed acid of HNO3-HClO4(4+1) in succession, and for determination of Cu(Ⅱ), the sample was acidified with 1 drop of H2SO4(2+8). Linear relationships between values of absorbance and mass concentration were kept in the ranges within 10 mg·L-1 for chromium and within 50 mg·L-1 for copper, with detection limits (3s/k) of 0.01 mg·L-1 and 0.1 mg·L-1 respectively. On the base of substantial water samples, standard solutions of Cr(Ⅵ) and Cu(Ⅱ) were added separately and determined by the proposed method to test for the recovery, giving results in the range of 84.5%-113% and 88.9%-105% respectively.