ADSORPTIVE STRIPPING VOLTAMMETRIC BEHAVIOR OF COPPER(II) AT A HANGING MERCURY DROP ELECTRODE IN THE PRESENCE OF EXCESS OF IMIDAZOLE


ERTAS F. N. , MOREIRA J., FOGG A.

ANALYST, cilt.116, ss.369-372, 1991 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 116 Konu: 4
  • Basım Tarihi: 1991
  • Doi Numarası: 10.1039/an9911600369
  • Dergi Adı: ANALYST
  • Sayfa Sayıları: ss.369-372

Özet

In the presence of excess of imidazole (1.0 x 10(-3) mol dm-3), copper(II), at pH 8.5, adsorbs at a hanging mercury drop electrode to give two adsorptive stripping voltammetric peaks at -0.36 and -0.46 V. The peak at -0.36 V is only present at accumulation potentials more negative than -0.05 V versus Ag-AgCl: it increases in height as the accumulation potential becomes more negative up to and beyond -0.6 V, the voltammetric sweep being started at -0.20 V. This peak appears to be due to the adsorption of polymeric [Cu(II)(lm)2] or its reduced copper(I) form. The peak at -0.46 V is only present at high imidazole concentrations (> 5.0 x 10(-4) mol dm-3): the accumulation is uniform from 0.0 to -0.36 V but is negligible at potentials more negative than -0.46 V. This peak appears to be due to adsorption of [Cu(lm)4]2+. On cycling between 0.0 and -0.6 V this latter complex is converted into the polymeric complex and only the peak at -0.36 V remains. Copper(II) can be determined by using the peak at -0.46 V after accumulation at 0.0 V, or at -0.36 V after accumulation at -0.6 V. The latter method is more sensitive: the detection limit is about 2.0 x 10(-9) mol dm-3 after accumulation for 3 min.