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Location of end-points in high-precision coulometry
Talanta
|July 1, 1975
Summary
This study used computer analysis to fit cubic equations to experimental data from high-precision coulometric titrations of weak bases. The findings show good agreement between end-points calculated using time and pH as variables.
Area of Science:
- Analytical Chemistry
- Computational Chemistry
Background:
- High-precision coulometric titrations are essential for accurate chemical analysis.
- Determining accurate end-points is critical for reliable titration results, especially for weak bases.
Purpose of the Study:
- To evaluate the accuracy of end-point determination in coulometric titrations using computational methods.
- To compare end-point calculations based on time versus pH as the independent variable for weak bases.
Main Methods:
- Utilized a computer to fit a cubic equation to experimental data from coulometric titrations.
- Analyzed titration data for 4-aminopyridine and tris(hydroxymethyl)aminomethane.
- Calculated end-points by identifying points of inflection (second derivative = zero) using both time and pH as independent variables.
Main Results:
- A cubic equation was successfully fitted to the experimental data in the end-point region.
- The end-points determined using time as the independent variable showed good agreement with those determined using pH.
- This method proved effective for analyzing weak bases like 4-aminopyridine and tris(hydroxymethyl)aminomethane.
Conclusions:
- Computer-assisted cubic equation fitting provides a reliable method for determining end-points in high-precision coulometric titrations.
- The choice of independent variable (time or pH) does not significantly affect end-point accuracy for these weak bases when using this computational approach.
- This technique enhances the precision and reliability of coulometric titration analysis.
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