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Updated: Jul 23, 2025
A New Straightforward Method for Lipophilicity logP Measurement using 19F NMR Spectroscopy
Published on: January 30, 2019
A pH-responsive sensor based on intramolecular internal standard for reproducible detection of strong acids and bases
1Department of Chemistry, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju, 61005, Republic of Korea.
Abstract:
Numerous methods, including pH meters and optical sensors, have been developed for the detection of pH, which is an important indicator in various fields. However, those methods are susceptible to errors in strongly acidic and basic ranges and inaccurate pH measurement due to sample turbidity, hindering their application such as photographic industries and wastewater treatment facilities. Eco-friendly and non-invasive 19F NMR spectroscopy is a promising technique for measurement of strong acids and bases owing to its high sensitivity and little interference; nevertheless, inconsistencies in reproducibility impede its widespread adoption. Herein, we developed a19F NMR-based pH sensor by introducing an intramolecular internal standard strategy into a pH-responsive fluorinated material. Based on the acceptable deviation (ΔδF = 17-19 ppb) in the evaluation of the internal standard signal, this pH-sensing platform enabled reproducible pH measurements in strongly acidic and basic environments. Moreover, its 19F NMR response showed reversibility and high stability to potential interfering factors, and the low absolute difference (0.026-0.086 in pH) for real samples such as diet Coke suggests its potential suitability for various acidic beverages.
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