For comparison studies, a platinum wire
electrode (Tacussel, diameter 1 mm, height 15.7
mm) was used. A Wenking model HP 70 poten-tiostat and an exact-type 250 function generator
were employed for the application of pretreatment
to the glassy carbon electrode. Spectrophotomet-ric measurements were carried out using a Shi-madzu UV 160 spectrophotometer witha1cm
quartz cell