Development of a pH Nano-sensor based on Electrochemical Impedance Spectroscopy in Order to Use in Rumen Monitoring System

It is necessary to use methods to monitor the pH of the rumen and maintain it between 5.5 and 7. In this research, a pH Nano-sensor based on EIS technique was developed and assessed in order to be used in wireless monitoring system of rumen pH. Single-Wall Carbone Nanotubes were functionalized with carboxylic groups (COOH), also with Amin groups (NHRNH2). Then interdigitated chrome-gold electrodes were coated by a drop of the solution obtained from dispersing with a known ratio of COOH-SWNT and Amin-SWNT in PECH/THF solution. Finally, the developed electrode was used as working electrode in EIS experiments over the laboratorial and real (rumen liquid) samples in the form of buffer solutions, adjusted at various pH values. Each experiment was done by applying AC voltages of 20 mV with frequencies ranging from 0.1Hz to 1MHz. Results showed that the developed electrode was pH sensitive and for real samples, impedance modulus, |Z|, linearly increased with pH (Freq.=0.4kHz, R2 =0.99).