ELECTROCHEMICAL pH MEASUREMENT

摘要

An electrode for the determination of pH is made by depositing a phenolic compound on a conductive substrate, where the phenolic compound has a phenolic hydroxy group attached to a carbon atom on an aromatic ring and also has an oxygen atom connected through one other atom to an adjacent carbon atom of the aromatic ring such that this oxygen atom can form a hydrogen bond to the phenolic hydroxy group; and then electrochemically oxidising the immobilized phenolic compound in a one electron one proton oxidation so as to form a polymeric, water-insoluble, redox-active deposit on the conductive substrate. The electrode is useful for electrochemical determination of pH and is capable of measuring pH of an unbuffered aqueous liquid.

主权项

1. A method of measuring the pH of an aqueous liquid wherein the concentration of buffer is not greater than 0.01 molar, comprising:
preparing a sensor electrode by applying a phenolic compound to a conductive substrate,
where the phenolic compound has a phenolic hydroxy group attached to a carbon atom on an aromatic ring and also has an oxygen atom connected through one other atom to an adjacent carbon atom of the aromatic ring, such that said oxygen atom can form a hydrogen bond to the phenolic hydroxy group; electrochemically oxidising the phenolic compound in a one electron one proton oxidation so as to form a polymeric, water-insoluble, redox-active deposit on the conductive substrate; and exposing the aqueous liquid to the sensor electrode and observing the redox reaction of the deposit on the sensor electrode.