Evaluation of the Micro-Antimony Electrode

Abstract

The micro-antimony electrode frequently gave intraoral plaque readings which deviated from glass electrode readings by 0.3 pH unit or more, the maximal deviation observed being 1 pH unit. The differences in pH readings between the 2 instruments do not necessarily result from inaccuracy of the antimony electrode alone. Observations of pH on saliva demonstrate that interfering agents may be present causing the micro-antimony electrode to give up to 0.4 pH unit higher readings than the glass electrode. The effect of a number of interfering substances such as, lactic, pyruvic, tartaric, succinic, acetic and thioglycolic acid, peroxide and Ca and P ions, which may occur in the mouth was studied at different concentrations. Under certain conditions, intraoral pH measurements obtained with the micro-antimony electrode may be expected to be only approximately correct. The micro-antimony electrode gives accurate in vitro pH readings in a number of acids and is well suited for certain electrometric micro titrations.