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Here is a full explanation of each slide in the presentation on Capillary Electrophoresis (CE):

Slide 1 - Title Slide

"Principle and Instrumentation of Capillary Electrophoresis" This is the title slide, announcing the topic: a deep look at how capillary electrophoresis works and what equipment is used.

Slide 2 - Table of Contents

Lists 15 topics covered in the presentation: Introduction, Electrophoresis Overview, Importance of separation techniques, Why CE, What is CE, Types of CE, Theory, Electroosmotic Flow, Electroosmotic Mobility, Flow in CE, Electropherogram, Equipment, Methods for improving efficiency, Applications, and Summary/Conclusion.

Slide 3 - Section Header

A visual divider slide introducing the "Capillary Electrophoresis" topic section.

Slide 4 - Introduction

In the modern pharmaceutical era, separating different components from complex mixtures is a major challenge. Various techniques exist, but for small-volume samples, capillary electrophoresis stands out as one of the most efficient. This slide sets the stage by stating the presentation will cover the basic theoretical concepts and principles of CE.

Slide 5 - Electrophoresis: An Overview

Definition: Electrophoresis is the differential movement (migration) of ions driven by attraction or repulsion in an electric field. It separates components of a mixture based on how they move in that field.

Key formula: v = Eq/f

v = velocity of the molecule
E = electric field strength
q = net charge of the molecule
f = friction coefficient (related to size/shape)

So larger charge = faster movement; larger/heavier molecules = slower movement.

Slide 6 - Electrophoresis Overview (continued)

Electrophoresis can reveal the size, shape, and charge of molecules. Different variants of electrophoresis are used depending on which property you want to measure - sometimes one factor alone, sometimes a combination.

Slide 7 - Types of Electrophoresis

Four main types are listed:

Capillary electrophoresis (CE) - the focus of this presentation
Native PAGE (Polyacrylamide Gel Electrophoresis) - separates proteins by size/charge in a gel
Slab electrophoresis - flat gel format
Paper electrophoresis - uses paper as the medium

Slide 8 - What is Capillary Electrophoresis?

CE places a positive electrode (anode) and negative electrode (cathode) in an ion-containing solution. When voltage is applied:

Cations (positive ions) migrate toward the cathode
Anions (negative ions) migrate toward the anode

CE specifically performs this separation inside narrow-bore, buffer-filled capillaries that are normally 25 to 100 µm in internal diameter (ID). The tiny bore is key to its performance.

Slide 9 - CE Methodology

CE has been used in research since 1980. Recent technological advances have made it practical for routine clinical use:

Multichannel instruments (multiple capillaries run simultaneously)
Fast separations
Positive sample ID
Full automation

In 2001, the company SEBIA launched the Capillarys system, which brought CE into clinical diagnostics (e.g., protein electrophoresis for serum).

Slide 10 - CE Instrumentation: The Basics

Expands on the principles:

Capillaries are 25-100 µm in internal diameter
Voltage applied causes molecules to migrate through the buffer toward the opposite electrode
Molecules of different charge migrate at different speeds, achieving separation
Separation can be based on charge or size

Slide 11 - Basics (continued): Detection

A photocathode (detector) measures the absorbance of molecules as they pass through a detection window on the capillary. These absorbance readings are captured by a computer and displayed as a graph (the electropherogram).

Slide 12 - Diagram Slide

An image-based slide showing a visual diagram of the CE system. The text is embedded in an image, but it illustrates the overall layout of the CE apparatus (capillary, electrodes, detector, power supply).

Slide 13 - Continuation Diagram

Another image/diagram slide continuing the visual explanation of CE setup or components.

Slide 14 - Electroosmotic Flow (EOF) in Minicap/Capillarys

This slide explains how CE works in clinical instruments (Minicap/Capillarys by SEBIA):

Cathode (-) on the left, Anode (+) on the right
Serum is injected at the anodic end; proteins are detected at the cathodic end
The Electroosmotic Flow (EOF) - driven by positive charges in the buffer interacting with the negatively charged capillary wall - is stronger than the individual electrical migration forces
As a result, all proteins are carried toward the cathode, regardless of their own charge, and are separated along the way based on their electrophoretic mobility

Slide 15 - CE Apparatus (Image)

A labeled image of the capillary electrophoresis apparatus showing its physical components.

Slide 16 - CE Apparatus (Image continued)

Another image showing the CE apparatus, likely a closer view or different angle/diagram of the equipment.

Slide 17 & 18 - Apparatus Diagrams (Continued)

More visual/image slides continuing the detailed illustration of CE components and how they connect (power supply, buffer vials, capillary, detector, etc.).

Slide 19 - Comparison of CE with HPLC

CE and HPLC (High-Performance Liquid Chromatography) are analogous:

CE Component	HPLC Equivalent
Power supply (voltage)	Pump (pressure)
Capillary	Column

Both use similar software frameworks. This comparison helps people familiar with HPLC quickly understand CE instrumentation.

Slide 20 - Electroosmotic Flow (EOF)

EOF is described as a vitally important feature of CE. It is the bulk movement of liquid through the capillary driven by the electric field, and it arises from the interaction between the charged capillary wall and the buffer ions. The mechanism is explained further on the next slide.

Slide 21 - Stern's Model / Double Layer

This slide illustrates Stern's model of the electrical double layer at the negatively charged silica capillary wall. The negative charges on the wall attract positive ions (cations) from the buffer, creating a double layer. When voltage is applied, these cations move toward the cathode, dragging the bulk solution with them - this is EOF. The zeta potential is the electrical potential across this double layer.

Slide 22 - Electroosmotic Mobility

Zeta potential is the change in electric potential across the double layer and is:

Proportional to the charge on the capillary walls
Proportional to the thickness of the double layer
Affected by buffer pH (higher pH = more ionized silanol groups = more negative charge = stronger EOF) and ionic strength (higher ionic strength = compressed double layer = weaker EOF)

These factors allow the analyst to tune EOF by adjusting buffer conditions.

Slide 23 - Flow Profile in CE

CE's EOF has a flat (plug-like) flow profile, unlike HPLC's parabolic (laminar) flow profile:

In HPLC, frictional forces at column walls create a pressure drop, causing faster flow in the center and slower at the edges (parabolic)
In CE, the driving force (wall charge) is uniform along the capillary, so all molecules move at the same velocity regardless of their radial position

This flat profile minimizes zone broadening and yields very high separation efficiencies - CE can resolve species with mobility differences as small as 0.05%.

Slide 24 - Flow Profile Diagram

An image comparing the flat EOF flow profile in CE vs. the parabolic flow profile in HPLC, illustrating why CE achieves better resolution.

Slide 25 - The Electropherogram

The output of a CE run is an electropherogram - a plot of migration time (x-axis) vs. detector response (y-axis). It is analogous to a chromatogram in HPLC. The detector response is usually UV-visible absorbance or fluorescence, which is concentration-dependent. A typical electropherogram shows peaks for cationic, neutral, and anionic solutes in order of their migration time.

Slide 26 - Equipment: Capillary Tube

The capillary tube itself is described:

Normally 25-50 cm in length
Made of fused silica
Smaller internal diameter and thicker walls help prevent Joule Heating (heat generated by electrical resistance when current flows through the buffer)
Controlling Joule heating is important because excess heat broadens peaks and reduces resolution

Slide 27 - Sample Introduction

Only a few nanoliters (nL) of sample are injected - CE requires very small sample volumes. Two injection methods are used:

Hydrostatic (pressure) injection - applying pressure/vacuum to push sample in
Electromigration injection - briefly applying voltage to draw charged analytes into the capillary
Stacking technique - a preconcentration method where sample prepared in low-conductivity buffer stacks (concentrates) at the capillary inlet, improving sensitivity

Slide 28 - Equipment: Detectors

Four types of detectors are used in CE:

UV/Visible absorption - most common; detects compounds that absorb UV/Vis light
Fluorescence - highly sensitive; used for fluorescently labeled or naturally fluorescent compounds
Radiometric - for radioactively labeled substances
Mass Spectrometry (MS) - provides molecular weight and structural identification, the most powerful option

Slide 29 - Applications, Advantages & Disadvantages

Applications:

Carbohydrate analysis
Inorganic anions and metal ions
DNA profiling
Protein identification

Advantages:

Fast
Small sample size (nanoliters)
Relatively inexpensive
Automated

Disadvantages:

Cannot identify neutral species (they all migrate together with EOF and aren't separated by charge)
Joule heating can affect separation
Cannot discern molecular shape differences

Slide 30 - Summary

Seven key takeaways:

CE is based on the principles of electrophoresis
Migration speed is determined by size and charge
Small, highly charged solutes migrate faster than large, less charged ones
Bulk movement of all solutes is caused by EOF
EOF speed can be adjusted by changing buffer pH
EOF's flat flow profile yields high separation efficiencies
The output is called an electropherogram

Slide 31 - Conclusion

CE is described as the most efficient separation technique available for both large and small molecules. Key applications highlighted include:

DNA profiling
Protein identification
Detection of inorganic metals and ions

These can all be performed with high speed, minimal sample, and automation.

Overall theme: This presentation is a thorough introduction to capillary electrophoresis - covering its theoretical basis (electrophoresis, EOF, zeta potential), instrumentation (capillary, detector, power supply), practical considerations (Joule heating, flow profile), and real-world applications in clinical and analytical chemistry.

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