Zdrojový dokument:Sensing in electroanalysis. K. Vytřas, K. Kalcher, I. Švancara (Eds.). 2010, Volume 5.
Abstrakt:
The carbon paste electrode containing 17 % (w/w) of dispersed bismuth
powder, despite its well-known performance in electroanalytical stripping methods,
was also evaluated as a potential pH sensor. Potentiometric response to pH of
solutions was ascertained under batch and flow conditions and compared to that of
classical glass electrode. Continuous flow or flow injection modes of analysis
together with buffers of different pH were employed to study the behavior of
modified carbon paste electrode in thin layer cell. Proposed pH sensor exhibited
linear, sub-Nernstian response of -41.2 mV per pH unit within the working range of
pH 2 – 10 in mode of flow injection analysis. The longest response time registered to
sudden change in hydrogen ion activity was 40 s. The sensor works de facto
sequentially in two modes of operation, which is rather interesting feature described
for an electrochemical sensor.
