Instrumentation
A Varian Vista Pró (Melbourne, Australia) axially inductively coupled plasma atomic absorption spectrometer (ICP OES) and a Perkin Elmer Sciex Elan 6000 (Tornhill, Toronto, Canada) inductively coupled plasma mass spectrometer with pneumatic nebulization were used to carry out the measurements. A Yanaco Co. (Kobe, Kyoto, Japan) AES 2D - Y1550 electroanalyser, equipped with high purity Pt electrodes was employed to separate Cu from the analytes. The ICP OES and ICP-MS operational conditions are described in Table 1.