Potentiometric determination of acids and bases using a silica gel based carbon-epoxy indicator electrode

摘要

The construction and the application of a silica gel based carbon-epoxy indicator electrode for the potentiometric determination of acids and ba.'ies are described. The effect of composition of silica gel and carbon-epoxy, slope (mV/pH), linear response ( pH range) and the use for acid-base titrations were investigated. The data obtained for the acid-base titrations were compared with those obtained using a glass electrode in the same conditions. The electrode showed a linear response in the pH2 to 13 range with a slope of -:40.5 :i: 0.4 mV/pH (at 25 °C) and a response time of less than 15 s, The lifetime of the electrode was higher than one year (over 6000 determinations) with a decrease of only 5% of the initial potentiometric re- sponse. The silica gel based carbon-epoxy electrode showed excellent results in the end-point indication potentiometric titrations in determination of acids and bases. The miniaturiza- tion of the proposed electrode for flow injection analysis was investigated.