Large enhancement of sensitivity and a wider working range of glass pH electrode with amperometric and potentiometric responses

In this communication, a new four-electrode measurement system has been developed to improve the analytical performance of a glass pH electrode. The sensitivity of detection is greatly enhanced and the working range is widened. In this new configuration, the potentiometric response slope of the pH electrode, dE/dpH, could be as high as −669 mV in the pH range 4-10. Amperometric measurement could also be employed to monitor the pH of aqueous solution and the response sensitivity (dI/dpH) is ∼67 nA. A two-signal (i.e., potential and current) synchronous detection technology has been exploited for pH monitoring.