Evaluation of a high sensitivity PbO(2) pH-sensor

In this paper, a new high sensitivity potentiometric pH-electrode with a response in the acid region is proposed. It consists of a PbO₂-paraffin matrix deposited on graphite. Its simple construction and studies of some variables at 0.5 mol L⁻¹ ionic strength are reported. A direct relationship between the electric potential difference and the solution pH was observed for pH values ranging from 1.2 to 7.5. A slope greater than 100 mV/decade and a conditional electric potential of about 1250 mV were obtained. The results presented a high correlation with those from a conventional glass pH-electrode in complex matrix samples.