Antimony electrodes. Mucosal potential differences and buffer composition adversely affect pH measurements in the...

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Gastroenterology

Background:

• Antimony pH electrodes are cost-effective and robust for clinical use.
• Simple construction and low impedance facilitate recording with standard equipment.
• Previous studies noted potential inaccuracies in in vivo gastric pH measurements.

Purpose of the Study:

• To investigate the causes of erroneous high gastric pH values obtained with antimony electrodes in vivo.
• To develop a reliable method for accurate in vivo gastric pH measurement using antimony electrodes.
• To identify and correct for interferences affecting antimony pH electrode calibration.

Main Methods:

• In vivo gastric pH measurement using antimony and silver-silver chloride electrodes.
• Utilized an ion-permeable dialysis chamber to isolate electrodes from transmucosal potential difference.
• Developed a combination antimony pH electrode embedded in dental acrylic.
• Calibrated electrodes with commercial pH buffers, citrate buffers, and acetate buffers.

Main Results:

• Antimony electrodes produced erroneously high gastric pH values in vivo.
• Gastric transmucosal potential difference was identified as a source of interference.
• Commercial pH buffers caused erroneous readings due to organic components.
• Accurate pH readings were achieved using citrate or acetate buffers or a normogram correction.

Conclusions:

• A combination antimony pH electrode design minimizes interference for accurate in vivo measurements.
• Careful selection of calibration buffers (citrate, acetate) or normogram correction is crucial for accurate antimony pH electrode readings.
• The improved antimony pH electrode offers significant potential for clinical and research applications requiring reliable in vivo pH data.