Ultratrace analysis based on Hadamard transform capillary electrophoresis

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Separation Science

Background:

• Capillary electrophoresis (CE) is a powerful separation technique.
• Conventional CE has limitations in detecting analytes at very low concentrations (ultratrace levels).
• Laser-induced fluorometry offers high sensitivity but can be limited by sample injection volumes.

Purpose of the Study:

• To develop a highly sensitive method for ultratrace analysis.
• To enhance the detection limits of capillary electrophoresis.
• To explore the application of Hadamard transform in CE for improved sensitivity.

Main Methods:

• Hadamard transform capillary electrophoresis (HTCE) was combined with laser-induced fluorometry.
• A multiple sample injection technique based on Hadamard matrices was employed.
• Computer simulations were used to assess feasibility for detecting sub-single molecules.

Main Results:

• Sensitivity was substantially improved by increasing the order of the Hadamard matrix.
• An 18-fold enhancement in signal-to-noise ratio was achieved using a matrix of order 2047.
• Detection of an average of less than a single molecule was demonstrated as feasible, with clear signal peaks observable at 0.3 molecule levels.

Conclusions:

• Hadamard transform capillary electrophoresis offers a significant advancement for ultratrace analysis.
• This technique overcomes the limitations of conventional single-injection CE for detecting extremely low analyte concentrations.
• The developed method shows great potential for applications requiring ultra-high sensitivity.