چكيده فارسي :
In this study, sensitive potentiometric solid state pH sensors based on metal oxide nanoparticles electrodeposited on pencil lead electrode were reported [1-4]. The prepared electrodes were carefully characterized by SEM, XRD and electrochemical techniques. To miniaturize the prepared pH sensors, a stainless steel 304 needle was used as a reference electrode. Selectivity, response time, stability and reproducibility of the miniaturized pH sensor were studied and compared with conventional glassy pH electrode. According to experimental results, near-Nernstian slope and linearity over the pH range of 1.5˗12.5 were obtained for the developed sensors. The prepared electrodes represented high ion selectivity to mono-valence and multi-valence ions with Pot log KA,B values around 6.49. Fast response time of about 20 s in acidic medium and 50 s in alkaline medium, long-term stability and reproducibility in two months, simplicity of fabrication, low cost and accuracy makes these sensors a suitable choice for rapid pH recording in micro volume samples.
