Final Section Study Analytical Chem

Who invented Soxhlet Extraction?

Franz R. von Soxhlet

Advantages of Soxhlet Extraction

Automated, Cost effective

Drawbacks of Soxhlet Extraction

Large volume of organic solvents, Lengthy Extraction, Incomplete extraction due to low temp, Analyte loss because of side reaction

Solid Phase Extraction (SPE)

Exhaustive extraction technique, Extracting phase is solid, Applicable to liquid samples

Solid Phase Extraction (SPE)

Target analyte is selectively extracted on the solid phase

Solid Phase Microextraction (SPME) Advantages

Solvent-free, Environmentally friendly, automated, Portable, field analysis

Solid Phase Microextraction (SPME) Advantages

Non-exhaustive, amount extracted on fiber is proportional to analyte concentration, Extracted is independent from sample volume

Two modes of SPME

Direct Immersion (DI) or Headspace (HS)

Chromatography

One of the most widely used analytical techniques

Chromatography Advantages

separation of complex mixtures, high sensitivity, low detection limits

Chromatography Advantages

Wide variety of samples

Who discovered the early chromatogram?

Mikhail S.Tswett (1872-1919)

Which Chromatographers won 1952 Nobel Prize?

A.J.P Martin and R.L.M Synge

What is a chromatographic separation technique named after?

the physical state of the mobile phase used.

Major Components of GC

Mobile phase delivery system, Sample introduction system, Column, Detector, Data acquisition and processing unit

Molecular Level Interactions in Chromatography

Orientation Interaction (Keesom Forces), Induction Interaction (Debye Forces), Dispersion Interaction (London Forces), Donor-Acceptor Interactions

Mobile Phase for GC

Inert Gases are used as Mobile Phases (no interactions between solute and mobile phases)

Commonly Used GC Carrier Gases

Helium, Hydrogen, Nitrogen, Argon, Carbon Dioxide

Types of GC Columns

Open tubular Column (capillary column), packed column, packed capillary column

Key Steps in GC Column Fabrication

Capillary Surface Pretreatment, Capillary Surface Deactivation, Static Coating of the Stationary Phase

Key Steps in GC Column Fabrication

Immobilization of the Stationary Phase Film, Thermal Conditioning of the Column

Detectors in GC

Thermal Conductivity Detector (TCD), Flame Ionization Detector (FID), Electron Capture Detector (ECD)

Detectors in GC

Nitrogen-Phosphorous Detector (NPD), Flame Photometric Detector (FPD), Msss Spectrometer (MS)

Flame Ionization Detector Optimum Flow Rates

He 30, H2 30, Air 300 mL/min