A continuous flow system design for simultaneous determination of heavy metals in river water samples

A new design of a continuous flow system applied to the simultaneous determination of the concentration of zinc(II), cadmium(II), lead(II), copper(II), nickel(II), cobalt(II) and chromium(VI) in river water is described. A flow cell made in the laboratory, which has been patented, based on a ‘wall-jet’ configuration with a three-electrode system is described. Optimum conditions for the determination of the metal ions are reported. The detection limits and relative standard deviation values were 4.01×10−9 M and 0.078 for Zn(II), 1.76×10−10 M and 0.056 for Cd(II), 4.69×10−10 M and 0.134 for Pb(II), 2.29×10−10 M and 0.138 for Cu(II), 1.61×10−9 M and 0.093 for Ni(II), 1.91×10−9 M and 0.113 for Co(II), and 1.35×10−9 M and 0.081 for Cr(VI). The procedure was applied to a sample of water from the Arlanzón river and the results were compared with inductively coupled mass plasma spectrometry (ICP-MS) as reference method. The final aim of this work is to design a flow system, which can be automated.