Sorption of mercury(II) both in cationic and in anionic form was studied by
means of carbon paste electrodes modified with typical clay minerals (mont
morillonites) and with mica (biotite). Significant anionic exchange of mont
morillonites was found in complexing media such as solutions containing ace
tates and chlorides. Anionic sorption of [HgCl4](2-) can be used for the de
termination of Hg(II) in media with high content of chlorides. Linear calib
ration dependences were found in the concentration range 1.24 x 10(-7)-9.86
x 10(-7) mol/l (10 min accumulation at -1.2 V) and in the range 4.9 x 10(-
8)-1.74 x 10(-7) mol/l (15 min accumulation). Model samples of table water
and saline water were analysed. (C) 1999 Elsevier Science B.V. All rights r
eserved.