EVALUATION OF THE MICRO-ANTIMONY ELECTRODE

¹ Eastman Dental Dispensary, Rochester, N. Y.

1. 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 two instruments do not necessarily result from inaccuracy of the antimony electrode alone.

2. 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.

3. The effect of a number of interfering substances which may occur in the mouth has been studied at different concentrations.

4. Under certain conditions, intraoral pH measurements obtained with the micro-antimony electrode may be expected to be only approximately correct.

5. The micro-antimony electrode gives accurate in vitro pH readings in a number of acids and is well suited for certain electrometric micro titrations.