Detection of extremely low concentration of amino acids

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Detection of extremely low concentration of amino
acids

• Presented by
• Sam Y. Bae

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Why Amino Acids?

• They are basic building blocks of all living
  organisms.
• Traces of them prove existence of life, like on
  Mars, pursuit at JPL.
• And, their metabolic activities can be correlated
  to diseases, pursuit at UCLA.

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Little bit about amino acids

• 20 amino acids and more.
• Monomers ? polymers ? a 3D structure like
  enzymes, functioning unit, like a lock-and-key.

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Specific Aim

• 3D-Plot of extremely low concentration of amino
  acids, each axis having separation-time,
  mass-to-charge ratio, and intensity.
• Through coupling capillary electrophoresis and
  mass spectrometer

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CEs AA separation

• Different size of AA are separated according to
  their Electrophoretic and Electrosmotic
  mobilities.

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Theory

• - Cation is a vector sum of ?EOF ?e
• - Anion is a vector sum of ?EOF - ?e
• - Neutral moves along with ?EOF

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Schematic Diagram
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Flourescamine LIF

• Attach fluorescent molecule ? Time vs. intensity.
• Below a typical electropherogram.

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MS AA detection

• Ionized particles deflected either by an electric
  field or magnetic field.
• Amount of deflection determined by each
  particles m/z.

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Mass Spectrometry
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CE and MS Plot Combined!
M/Z
Time
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So, I want to build an engineering system

• Capillary electrophoresis coupled with a mass
  spectrometerintermediated by a nano-Electropray
  ionization. This will enable detection of what
  were limitations in seeing low concentration
  molecules.
• CE and MS are mature technologies main
  development will be in fabrication of a nano-ES
  tip, which aerosolize analytes from/after a CE
  separation.
• Lab-on-a-chip will add automation in directing
  fluid to different analytical chambers.
  (Contamination should be kept minimum for low
  concentration detection.)

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Preliminary Results

• Directing a sample through a Lab-on-a-chip
• Simultaneous analysis on a chip
• No human interference, minimum contamination

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Nano-Electrospray Tip

• On-chip nano-ES tip
• Autonomous, eliminates manual assembly of nano-ES
  and CE ? Consistency, low contamination
• Sheethless flow ? Precision spray volume
• On-chip ? Minimum band broadening in separation
• A successful nano-ES tip is
• 30-micron diameter via that is
• Connected immediately end of a 0.4-mm CE
  capillary wafer
• Has the same axial area as the capillary channel
• Is made of the same material as the channel

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Design

• Fabrication of nano-ES tip is essential in
  coupling on-chip CE an MS.

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Plans

• Establish optimal geometry of LOC for mixing and
  analysis and run an artificially mixed solution
  in CZE.
• Fabricate a nano-ES tip and establish sprayed
  ions current values.
• Couple the chip to an MS.
• Run amino acids