Comparison of a single‐use pH test strip and a glass electrode for potentiometric titration

• Published in: Journal of the Chinese Chemical Society (Taipei) Vol. 70; no. 7; pp. 1532 - 1536
• Main Authors: Wang, Hsing‐Ting, Kuo, Fang‐Ci, Lin, Xin‐Yuan, Tsai, Hwei‐yan
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley‐VCH Verlag GmbH & Co. KGaA 01.07.2023; Wiley Subscription Services, Inc
• Subjects: Acid-base neutralization; Ammonia; analytical chemistry laboratory; Electrodes; experimental waste reduction; Mixtures; Monitoring; pH sensor; potentiometric titration; screen‐printed electrode; Strip; Titration
• ISSN: 0009-4536; 2192-6549
• DOI: 10.1002/jccs.202300103

The potentiometric titration of a carbonate mixture or an acetate solution is a common experiment in analytical laboratories. Typically, a glass electrode combined with a calomel or Ag/AgCl reference electrode is used to locate the equivalence points in neutralization titrations. The dissociation constants of weak acids and bases can be calculated from the pH at the half‐neutralization point. Recently, a new commercial product for measuring pH has been developed. This novel acid–base detection strip is a single‐use sensor that requires neither storage in a preservation liquid nor calibration prior to use. This study examined its suitability for the continuous monitoring of pH changes in potentiometric titrations of carbonate mixtures, acetate solutions, or ammonia solutions. There were no significant differences in the concentrations of solutions tested using a glass electrode and a pH test strip. The pKa, pKb, and pH values determined using the two systems differed by less than 5%. The results confirmed that the pH strips are suitable for continuously monitoring pH changes during neutralization titrations. However, the strips can only be used once. A new commercial product which is carbon based with acetaminophen as the pH detection layer. It is a promising alternative device for the potentiometric titration of neutralization experiments. The pKa, pKb and pH values determined using the glass electrode and the strip‐pH electrode systems differed by less than 5%. The Humming Probe® UH1 pH strip was suitable for the potentiometric titration of the neutralization experiments and for determining the dissociation constants of weak acids and bases.