Brittany Hicks
GC-MS & GC-FID Lab- Dr. Foy
Spring 2013
Gas Chromatography Lab
Introduction
There are two main types of gas chromatography, with differences comprised of their detectors.
Gas chromatography mass spectroscopy is comprised on a gas chromatograph and a mass
spectrometer. Using a gas chromatograph, phase properties and a capillary column dimension aids in
the utilization of this instrument. The main compounds that the GC-MS analyzes are volatile organic
compunds.
The second type of gas chromatography is gas chromatography with a flame ionized detector.
This includes the same set up as the GC-MS with an injection site, pump, but a different detector. The
flame ionization detector is best for analyzing hydrocarbons and also compounds that are easily
flammable. Detection involves monitoring the current of a desired sample by collecting the different
charge carriers.
The purpose of this experiment to familiarize ourselves with both types of gas chromatography
and apply the techniques used to analyze samples. There will be a variety of known samples for
comparisons of unknown samples in detection.
Procedure – GCMS
1. Make sure the Helium flow in the Gas Room is on and the pressure gauge is at 80 psi or above.
The Helium flow should always be on. Make sure the Helium flow behind the instrument is on.
2. Open the software by clicking the 1st icon on the menu bar on the top of the screen – System
Control
3. Click on Acquisition, then File - Activate Method and choose the method named “Instrumental
2012 GC-MS Method.”
4. Click View/Edit Method along the top of the screen. Under GC Control, make sure all split states
are turned on.
5. Wait for both the software and instrument to show all green “Ready” lights. If they continue to
say “Not Ready” click Reactivate on the method bar.
6. Using a clean syringe with a sharp tip, rinse the syringe about 3 times with hexane or acetone.
Do this before each new sample.
7. Fill the syringe with 1 microliter of sample followed by 1 microliter of air.
8. Push the needle through the middle of the metal circle on top of the instrument until the metal
is touching the instrument and inject the sample.
9. The software should automatically begin to read the sample, but if it doesn’t click Start
Acquisition. The software will run for about 10 minutes per sample.
10. When the spectrum is completed, click MS Data Review on the top bar of the screen. Right click
the main peak on the spectrum and select Library Search Spectrum. This will identify the peaks
and retention times.
11. Save the file and print the spectra if possible. If printer is not connected, Print Screen and save
spectra onto a USB drive.
12. Close all windows to shut down software and instrument. Do not turn off computer or Helium
gas flow behind instrument or in Gas Room.
Procedure – GC FID
1. In the Gas Room, make sure the Helium flow is on. Turn on the Compressed Air and Hydrogen
flows. Make sure all tanks’ pressure gauges are at 80 psi or higher.
2. Turn on the Compressed Air and Hydrogen flows behind the instrument. Also make sure the
Helium flow is on.
3. Turn on the instrument by switching on the black button on top of and towards the back of the
instrument. Do not touch any other buttons on the instrument.
4. Click the System Control icon on the top left of the screen to open the software.
5. Click on File – Activate Method. Choose “bio-diesel-Hu.mth” as your method.
6. You should hear a loud “pop” indicating that the flame is lit inside the instrument. To check that
the flame is lit, use the metal spatula to lift the top of the right side on the instrument. Hold the
spatula over the metal tube, and if fog appears the flame is on. If it is not, click Reactivate in the
method bar.
7. After all red lights on the screen turn green, the software will continue to say “Waiting.”
However, if all temperatures shown on the screen have been reached and the instrument is
detecting signal, you can begin to run samples.
8. Using a clean syringe with a sharp tip, rinse the syringe about 3 times with hexane or acetone.
Do this before each new sample.
9. Fill the syringe with 1 microliter of sample followed by 1 microliter of air.
10. Push the needle through the middle of the metal circle on top of the instrument until the metal
is touching the instrument and inject the sample.
11. The software should automatically begin to read the sample, but if it doesn’t click Start
Acquisition. The software will run for about 10 minutes per sample.
12. When the spectrum is completed, click the Review/ Process MS Data icon on the top of the
screen. On the spectrum’s menu bar, click the 4th icon from the left Integrate Area. Drag the
cursor along the bottom of the prominent peaks to find retention times.
13. Save the file and print the spectra if possible. If printer is not connected, Print Screen and save
spectra onto a USB drive.
14. Close all windows to shut down the software. Switch off the button on top of the instrument to
shut it down. Turn off the Compressed Gas and Hydrogen flows behind the instrument and in
the Gas Room. Do not turn off computer or Helium gas flow behind instrument or in Gas Room.
Data and Analysis
These are the results we received from the GC-FID. There were good peaks observed and the results also
show retention times associated with all of our samples.
Unfortunately, the GC-MS did not produce any good data to include within this lab report. The
instrument kept reading an error message which ultimately caused the spectra from this experiment to
be lost before being able to save them. All of the major peaks shown and their retention times are
recorded In my lab notebook, but there are no spectra to correlate with them. I
Conclusion
Overall this experiment was not very good. The GC-MS provided error messges that deleted the
spectra by closing the program before I could fully analyze them and save the images. Fortunately
though I wrote down all of the major peaks and retention times associated with these peaks. The GCFID also gave us an error message, but we were able to completely save the spectra. Different peaks
were shown among this experiment, but we were able to analyze them and their retention times easily.
We also experienced an error with the flame multiple times. It would not fully light so this could have
caused errors within our data.