Capillary ElectrophoresisCapillary Electrophoresisa.k.a. CE, CZE, HPCEa.k.a. CE, CZE, HPCE

Separation is based on differences Separation is based on differences in solute mobilities when a strong in solute mobilities when a strong electric field is applied across a electric field is applied across a

bufferbuffer

Advantages (Vs. HPLC)Advantages (Vs. HPLC)

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Velocity of Flow can be altered by:Velocity of Flow can be altered by:

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ApplicationsApplications

Can detect very Can detect very small amounts of small amounts of substances substances atamolar 10atamolar 10-18-18!!

Detection of Alkylated Detection of Alkylated Cellulose Derivatives in Cellulose Derivatives in Several Archaeological Linen Several Archaeological Linen Textile Samples by CE/MSTextile Samples by CE/MS

Identification of Proteins in Identification of Proteins in Single-Cell CE Fingerprints Single-Cell CE Fingerprints Based on Comigration with Based on Comigration with

Standard ProteinsStandard Proteins

Postelectrophoresis Capillary Postelectrophoresis Capillary Scanning Method for DNA Scanning Method for DNA Sequencing Sequencing

Extraction of Rutin from Extraction of Rutin from Buckwheat (Buckwheat (Fagopyrum Fagopyrum esculentum esculentum Moench) Seeds Moench) Seeds and Determination by CEand Determination by CE

Electrochemistry ReviewElectrochemistry Review

Represent the above Represent the above electrochemical cell in electrochemical cell in standard notationstandard notation

What species is being What species is being oxidized in each cell? oxidized in each cell? Reduced?Reduced?

Predict the voltage that will be Predict the voltage that will be measured when activities are measured when activities are 1.01.0

Predict the voltage when Predict the voltage when [ZnSO[ZnSO44] is 0.010M] is 0.010M

What is the cathode and what What is the cathode and what is the anode?is the anode?

Is this an electrolytic or Is this an electrolytic or galvanic cell?galvanic cell?

Useful info: Useful info:

ZnZn2+2+ + 2e + 2e-- Zn(s) Zn(s) -0.763V -0.763V

CuCu2+2+ + 2e + 2e-- Cu(s) Cu(s) +0.337V +0.337V

0.2M CuSO4

1M ZnSO4

ZnCu

ElectrochemistryElectrochemistry

HH22 electrode reference electrode electrode reference electrode

Defined as 0.00V at all temperaturesDefined as 0.00V at all temperatures

Solid calomel electrode also used as Solid calomel electrode also used as reference but its potential is 0.2444V reference but its potential is 0.2444V relative to Hrelative to H22

By convention: Electrode potentials By convention: Electrode potentials are written as reduction potentialsare written as reduction potentials

ExampleExample

A Cu penny can be dissolved in nitric A Cu penny can be dissolved in nitric acid but not in hydrochloric acid. acid but not in hydrochloric acid. Using reduction potentials from the Using reduction potentials from the book, show why this is so. What are book, show why this is so. What are the products or expected products of the products or expected products of each reaction?each reaction?

Ion Selective ElectrodesIon Selective Electrodes

pH electrodespH electrodes

In solution to be measured, external ions In solution to be measured, external ions diffuse through membrane until diffuse through membrane until equilbrium is achieved, creates a build up equilbrium is achieved, creates a build up of charge proportional to #H+ in external of charge proportional to #H+ in external solutionsolution

Millivolt meter measures this potential Millivolt meter measures this potential differencedifference

pH electrodespH electrodes

Reference Reference electrodeselectrodesMust be in contact Must be in contact with ISEwith ISEAllows balancing of Allows balancing of chargecharge

E = EE = E00 + (2.303RT/ + (2.303RT/ nF) x Log(A) nF) x Log(A)

Differences between pH electrodes Differences between pH electrodes and other ISEand other ISE

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Schematic Diagram of ISESchematic Diagram of ISE