Simultaneous comparison of 24-hour intragastric pH recording using glass and antimony electrodes in man

Based upon the results of in vitro studies, antimony electrodes are generally considered to have inferior electrochemical properties when compared with glass electrodes. Since a direct comparison in man is lacking, a 24-hour ambulatory intragastric pH recording was performed in 10 healthy male subjects simultaneously using glass and antimony electrodes. In the first set of experiments (when both electrodes were calibrated in buffers of pH 7 and 1 at 37 degrees C: beaker calibration) significantly lower pH recordings during fasting periods were registered with the antimony electrode. This difference could be corrected by a modified calibration, using the external skin reference electrode of the antimony electrode (finger calibration). In the second series of experiments (performed after finger calibration) comparable recordings of 24-hour intragastric pH could be obtained with antimony and glass electrodes in the same subjects. The reason for statistically insignificant differences of pH recordings with both electrodes in the early hours of the morning remains uncertain. The drift of glass and antimony electrodes did not differ. It is concluded from these data that, after adequate calibration, inferior electrochemical properties of antimony electrodes do not influence intragastric pH recordings in man.