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Multivariate calibration methods for quantification in strongly overlapping capillary electrophoretic peaks.
S Sentellas1, J Saurina, S Hernández-Cassou
1Department of Analyitcal Chemistry, University of Barcelona, Spain.
Journal of Chromatography. A
|March 28, 2001
Summary
Capillary electrophoresis struggles with neutral ebrotidine metabolites due to overlapping peaks. Chemometrics, specifically partial least squares (PLS), successfully quantified these analytes in mixtures with 9.7% error.
Area of Science:
- Analytical Chemistry
- Biochemistry
- Pharmacology
Background:
- Capillary zone electrophoresis (CZE) with diode-array detection (DAD) is a common technique for separating drug compounds and their metabolites.
- Neutral metabolites can co-migrate with the electroosmotic flow (EOF) in CZE, leading to peak overlap and quantification challenges.
- Ebroditidine and its metabolites present a separation challenge due to the neutral nature of some key metabolites under specific CZE conditions.
Purpose of the Study:
- To demonstrate the utility of capillary electrophoresis (CE) coupled with chemometric methods for analyzing challenging analyte mixtures.
- To develop and validate a multivariate calibration model for the accurate quantification of ebrotidine metabolites.
- To overcome peak overlap issues encountered in the separation of neutral ebrotidine metabolites.
Main Methods:
- Capillary zone electrophoresis (CZE) with diode-array detection (DAD) was employed for the initial separation of ebrotidine and its metabolites.
- Chemometric multivariate calibration, specifically partial least squares (PLS), was applied to resolve overlapping peaks and quantify analytes in synthetic mixtures.
- Validation of the PLS model was performed by comparing quantified values against known concentrations in synthetic samples.
Main Results:
- Neutral ebrotidine metabolites co-migrated with the electroosmotic flow (EOF), causing significant peak overlap in standard CZE-DAD analysis.
- The partial least squares (PLS) multivariate calibration method effectively resolved the overlapping peaks, enabling accurate quantification of the target analytes.
- The PLS model achieved good agreement with actual analyte values in synthetic mixtures, with an overall prediction error of 9.7%.
Conclusions:
- Capillary electrophoresis, when enhanced by chemometric techniques like PLS, offers a powerful solution for quantifying analytes with overlapping peaks.
- This approach successfully addresses the limitations of traditional CZE-DAD for analyzing complex mixtures containing neutral metabolites.
- The study highlights the potential of CE-chemometric combinations for robust pharmaceutical analysis and metabolite profiling.