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ID 116829
Author
Ochiai, Junya Tokushima University
Oka, Sawako Tokushima University
Hirasaka, Tomoko Tokushima University
Tomiyama, Erina Tokushima University
Kubo, Hiroya Tokushima University
Okamoto, Kazumasa Tokushima University
Keywords
Flow titration
flow ratiometry
feedback-based control
triangular wave control
air-segmentation
nonaqueous titration
Content Type
Journal Article
Description
An air-segmentation approach has been introduced to a feedback-based and subsequent fixed triangular wave-controlled flow ratiometry to suppress axial dispersion in flow titration. The flow rate of a base solution containing an indicator is linearly varied with a control signal, Vc, supplied by a computer. The solution is merged with an acid solution under a constant total flow rate. Air is introduced to the merged solution in order to segment the solution with air bubbles. Both phases are led to a UV/Vis detector without phase separation. Air signals are removed by signal processing. The effect of the lag time between the merging of solutions upstream and the sensing of the corresponding signal downstream is offset by feedback-based upward and downward Vc scans, and thus the Vc that gives the equivalence composition is determined. Subsequently, fixed triangular wave control is applied to a narrower Vc range with a higher scan rate to enhance the throughput rate (maximally 11.8 titrations/min). Air-segmentation has been found to be effective to reduce axial dispersion and to preserve the titrand/titrant composition upon their just being merged. Consequently, the applicable range is extended especially to lower titrand concentration. The proposed method has been successfully applied to various acid-base titrations, including the nonaqueous titration of the Japanese Pharmacopoeia drug.
Journal Title
Analytical Sciences
ISSN
13482246
09106340
NCID
AA10500785
Publisher
The Japan Society for Analytical Chemistry
Volume
36
Issue
6
Start Page
703
End Page
708
Published Date
2020-06-10
EDB ID
DOI (Published Version)
URL ( Publisher's Version )
FullText File
language
eng
TextVersion
Publisher
departments
Pharmaceutical Sciences