A SIMPLE AND VERSATILE PSA SYSTEM FOR HEAVY-METAL DETERMINATIONS

An easy to build potentiometric stripping analysis system for heavy me tal determinations (Zn, Cd, Pb, Cu) is described which reaches good se nsitivity and precision. Main components are an IBM compatible compute r, an ADDA-conversion card and two selfmade electrodes, so it can be r ealized for one tenth of the price of complete commercial systems. A g raphite pencil lead covered with a Hg film is used as working electrod e and a Ag/AgCl electrode as a combined reference/counter electrode. R eproducibility and calibration measurements are reported, heavy metal determinations on soil samples are compared with AAS results.