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Queen's University
 

GC-MS/FID/ECD/TCD

Gas Chromatography with Mass Selective Detector, Flame Ionization Detector, Electron Capture Detector and Thermal Conductivity Detectors 

Organic Compound Analysis

 

 

Most of the organic analyses that we conduct are for organic priority pollutants such as pesticides, PCBs, PHCs, BTEX, and other petroleum products. Gas Chromatography (GC) is the standard methodology. From sample matrices such as soil, water, plants and fish, the analyte's are extracted into organic solvents, separated from interfering substances (cleaned up), concentrated and run on the GCs.

 

 


 

Agilent GC 

 


Using a variety of different detectors, excellent sensitivity and specificity can be achieved for a whole spectrum of  compounds. The use of automated sample carousels means that the GCs can be left unattended for overnight operation.

 

 

 Autosampler

Automated sample analysis on Agilent GC

 


The ASU possesses or otherwise has access to seven automated GC systems.  In addition, we have a Pyrolizer accessory for special (non-volatile) samples and a purge and trap unit for volatile organic compounds (VOCs).

 

 

For details on how a pyrolizer works:

 

 

How to Analyse Unknown Samples by Pyrolysis GC/MS, by Joeri Vercammen, Valérie Winne and Myriam Madani,

 

 

 

'Purge and Trap' GC/MS is used to look at volatile organic compounds. Typically, the organic compounds have to be concentrated prior to analysis and this is done by purging the analytes of interest from a sample using an inert gas. This purging process removes the compounds from the sample matrix and deposits them to an absorbent cartridge. This is then heated rapidly and the organics are removed into the GC/MS system in concentrated form.

  


Soxhlett Extraction

 

This glass apparatus was invented in 1879 and is still in use today. It uses the principle of 'continuous extraction' to repeatedly cycle solvent through a 'thimble' containing a material to be extracted.

 

See Wikipedia: Soxhlet Apparatus

 

 

 Soxhlett Extractionjpg

 Plant sample extraction, by soxhlet

 

 

 


Analytical Services Unit Jun 2014 

 

 Detectors and how they work

The Electron Capture Detector (ECD)

 

 An ECD Detector

See Agilent: eInspirations newsletter,2010 

 

For an excellent description of how an ECD detector works, visit the Feb 2010 Agilent, eInspirations newsletter.

 

 

The Flame Ionisation Detector (FID)

 

FID Detector

See UCDavis ChemWIKI for a complete description of how the FID works.

 

The Thermal Conductivity Detector (TCD)

 

 

Thermal Conductivity Detector

 

See UCDavis ChemWIKI for a complete description of how the TCD works.

 


Sample Preparation For GC Analysis

 

There are many 'method specific' methods we use to prepare our organic samples for GC analysis. Two of our primary solvent extraction methods utilize accelerated solvent extraction (ASE) or soxhlet extraction  techniques.

 

 

 

ASE Extraction.jpg

Dionex ASE200 Solvent Extractor

 

 


Typical PCB Chromatogram

 

PCB Chromatogram.JPG

 

Reproduced from " β-cyclodextrin enhanced phytoremediation of aged PCBs-contaminated soil from e-waste recycling area"

 

Yingxu Chen * a, Xianjin Tang a, Sardar Alam Cheema a, Wenli Liu b and Chaofeng Shen a 
 

 


 

Kingston, Ontario, Canada. K7L 3N6. 613.533.2000