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Published on: February 15, 2018
Determination of acid dissociation constants based on continuous titration by feedback-based flow ratiometry
Hideji Tanaka1, Takahiro Tachibana, Risa Oda
1Faculty of Pharmaceutical Sciences, Tokushima University, Shomachi 1-78-1, Tokushima 770-8505, Japan.
Talanta
|October 31, 2008
Summary
This study introduces a novel method for determining acid dissociation constants (pK(a)) using feedback-based flow ratiometry to quickly find the equivalence point. This allows for precise pK(a) determination with high throughput and accuracy.
Area of Science:
- Analytical Chemistry
- Physical Chemistry
- Chemical Engineering
Background:
- Accurate determination of acid dissociation constants (pK(a)) is crucial for understanding chemical reactions and designing chemical processes.
- Traditional titration methods can be time-consuming and may lack precision.
- Automated and rapid analytical techniques are needed to improve efficiency in chemical analysis.
Purpose of the Study:
- To develop and validate a novel method for rapid determination of acid dissociation constants (pK(a)).
- To utilize feedback-based flow ratiometry for precise equivalence point (EP) detection.
- To establish a method for estimating the half equivalence point (EP(1/2)) for pK(a) calculation.
Main Methods:
- Employed feedback-based flow ratiometry, varying titrant flow rate in response to controller voltage.
- Utilized a knotted tubular mixer and downstream pH monitoring.
- Implemented a control strategy to detect EP during upward and downward voltage scans for EP(1/2) estimation.
- Automated studies on pK(a) dependence on ionic strength and dielectric constant.
Main Results:
- Achieved rapid determination of pK(a) with a throughput of 53 seconds per sample.
- Demonstrated high precision with a relative standard deviation (R.S.D.) of approximately 0.3%.
- Obtained satisfactory results for various acids, validating the method's applicability.
Conclusions:
- The proposed method enables fast and precise determination of acid dissociation constants.
- Feedback-based flow ratiometry offers an efficient approach for equivalence point detection in titrations.
- The technique is suitable for automated studies investigating factors affecting pK(a).
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