Electrodes of nontoxic solid amalgams for electrochemical measurements

The preparation, activation and electrochemical pretreatment of electrodes based on nontoxic solid amalgams were described. Testing of metal solid amalgam electrodes (MeSAEs) proved their broad applicability in many respects, e.g., as to the range of working potentials and the level of background currents, well comparable with those of the hanging mercury drop electrode (HMDE). A regeneration of their surfaces before each measurements could be simply automatized using a PC-controlled system providing a reasonable repeatability of voltammetric measurements down to 3% RSD. Combination with stripping techniques at accumulation times t(ac) 300 s the detection limit amounted to the concentration level of 1 ppb Cu(II), Pb(II), Cd(II), Zn(II), etc. Best electrochemical properties were exhibited by the silver solid amalgam electrode (AgSAE). For example, polished AgSAE (p-AgSAE), completely free of liquid mercury, proved satisfactory even at more negative potentials enabling the determination of Zn(II), Mn(II), IO3-, etc. Moreover, even better repeatability of mercury meniscus modified AgSAE (m-AgSAE) was due to better quality and renewability of its surface. In many cases further testing confirmed that under appropriate conditions MeSAEs represent good, often cheaper and more users-friendly alternatives to HMDE.