Abstrakt
The degree of passivation of the working electrode during the amperometric detection in flow can be strongly diminished by the application of pulsed amperometry, even without the application of specific cleaning pulses. Three different potential programs were tested and compared to the traditional amperometry with continuously applied potential.
All three programs suppressed the passivation in different degree, although the observed efficiency depends also on the conditions of the determination, particularly the pH of the electrolyte. Simple switching between the detection potential and zero potential provided the best results; more complex potential programs shower either the lower efficiency or the low measurement frequency.
The detection and quantification limit, obtained using this method, reached 5.8 x 10(-6) mol dm(-3) and 1.9 x 10(-5) mol dm(-3), respectively; their relatively high value is caused by the increase of the background current, inevitably caused by the potential changes.