Direct Hadamard Transform Capillary Zone Electrophoresis without Instrumental Modifications.

Area of Science:

• Analytical Chemistry
• Separation Science
• Biophysical Chemistry

Background:

• Standard capillary electrophoresis (CE) with UV detection suffers from low sensitivity.
• Enhancing signal-to-noise ratio is crucial for detecting low-concentration analytes.
• Existing methods for sensitivity enhancement often require specialized hardware.

Purpose of the Study:

• To implement a hardware-independent multiplexing method for standard CE.
• To improve the signal-to-noise ratio of UV detection in CE.
• To demonstrate the applicability of the method for complex sample analysis.

Main Methods:

• Utilized Hadamard transform for multiplexing in capillary zone electrophoresis.
• Employed vial exchange and voltage suspensions for injection control.
• Subdivided long sequences and realigned data based on EOF markers or analyte peaks.
• Investigated effects of voltage suspensions on electrophoretic zones and data quality.

Main Results:

• Achieved signal-to-noise ratio enhancement factors of approximately 6.9 and 5.2 for AMP and nucleotide mixtures, respectively.
• Successfully deconvoluted modulation sequences up to 8-bit (255 injections).
• Demonstrated practical application in analyzing a milk sample, confirming method applicability.
• Quantified the impact of electrophoretic errors on inverse Hadamard transform quality.

Conclusions:

• The developed multiplexing method is compatible with unmodified standard CE instrumentation.
• This approach provides a new, effective methodology to overcome the sensitivity limitations of on-column UV detection in CE.
• The technique offers a significant advancement for sensitive analysis of various samples, including biological and food matrices.