Rossi/Kuwata
Chemistry 222
Spring 2012
Directions for Using the HP 5890A Gas Chromatograph (GC/FID)
SETTING UP THE INSTRUMENT: FLOW RATES AND OTHER SETTINGS
Usually, Steps 1 – 6 will have been performed for you. Skip these steps unless you are told otherwise.
(Settings below were established for our new column [DB-5, 15 m long, 1.5 m thick stationary phase] by Rob Rossi, F09)
1. Turn on the GC (the switch is on the back corner on the right hand side) and the integrator (the push-on, push-off
switch is on the back left side of the integrator.)
2. Open completely the main valves of the three gas cylinders along the wall. Confirm that the regulators are set to the
following pressures: H2 at 30 psig, air at 30 psig, and He at 40 psi. (If not, set them to those values.)
3. Set flowrates for the flame ionization detector (FID) using the controls at the upper left of the instrument. The AUX
GAS (helium) valve should be completely closed, and never opened. Open the AIR and HYDROGEN valves
completely. After waiting at least 5 minutes, press the FID IGNITOR button; you should hear a pop if the FID lights.
Most likely, it won't stay lit, in which case you should click the sparker on the butane lighter above the exhaust port
for the FID until you no longer hear popping sounds when you do so. (No need to make the lighter provide a flame;
the spark is enough.) The flame comes from the exothermic reaction of H2(g) and O2(g). To check that the FID is
working, hold a watch glass over the detector vent: water vapor should condense on it.
4. Set the oven temperature to 30C and turn it ON.
5. See if the integrator printed anything out when you turned it on. If it didn't, the ink cartridge will need to be cleaned
or replaced: see Rob or Prof. Kuwata. Once that's fine and it is printing, hit the buttons ATT 2^ (at the top of the
keyboard), 6, and ENTER (this sets the attenuation of the peaks to 26 = 1); also press CHT SP, 2, ENTER (set chart speed).
6. Now program the GC. The injector and detector A port temperatures should be 200˚C. The oven should stay at 30˚C
for the entire run of 2.2 minutes. To make it shut off automatically, a non-zero rate value must be entered. Septum
purge should be off. The helium (the mobile phase in this experiment) should have a split flow rate of 100 mL/min.
If this has not been set for you already, here's how you set it:
a. Make sure the COLUMN HEAD PRESSURE is set to 3 psi.
b. Make sure the septum purge is off.
c. Connect the soap film flow meter to the SPLIT VENT outlet.
d. Charge the flow meter with some fresh soap solution.
e. Squeeze the bulb at the bottom of the flow meter to get a bubble flowing.
f. Adjust the knob above the SPLIT VENT until a bubble rises from zero to the 100-mL mark in 60 s.
OPERATIONAL CHECKS AND PROCEDURES
Usually, you will start here. If the GC is not on and ready, go back and do steps 1 through 6.
7. Sign the log book! (Please note, in both the log book and in your lab notebook, if you have any
problems with the instrument.)
8. Make sure the flame ionization detector (FID) is working by holding a glass watch glass just
above the detector vent. Water vapor should condense on it! You can also press the "SIG A"
button on the GC and confirm that the value shown is a stable, positive value, probably twentysomething but possibly in the thirties if another group has just finished up.
PERFORMING A GOOD INJECTION WITH THE 1 SGE SYRINGE! (OY, IT'S AUSSIE!)
You don't need to inject exactly 0.50  in each trial, but you need to inject the entire sample at once,
at it should be reasonably close to the target volume (such that your chromatograms look similar).
The SGE syringe is quite expensive! Please be careful with it, as we only have one, and it is MUCH
easier to use than the cheaper Hamilton syringes we will have to resort to if the SGE is damaged.
9. Before opening it, invert the volumetric flask containing the analyte of interest. (This mixes in
condensate off the inner wall, which may not have the same composition as the bulk.)
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Rossi/Kuwata
Chemistry 222
Spring 2012
10. Un-cap the volumetric flask and immerse the 1  SGE syringe needle in the analyte, almost up to
the knurled nut at the end of the barrel. Slowly draw the syringe up to the 1  mark, and then
quickly push it out again. [I actually tap it down rather than push it: you want to try to emulate the
action of the autosampler unit we saw on the GC/MS!] This process removes the air bubbles from
the syringe barrel and fills it with your analyte. [The liquid channel in this syringe is (far!) too
narrow to flick the bubbles out as you might with a larger syringe!] Repeat this process at least
three times, to remove all air bubbles and also thoroughly flush the syringe with your analyte.
11. With the syringe needle still well submerged, slowly draw up the plunger to the 0.5  mark.
Remove the syringe from the volumetric flask, and wipe the needle dry with a Kimwipe. Then
slowly pull the plunger back to the 1.0  mark, drawing in a "pad" of air for the injection. Do not
pull the syringe out further than the 1.0  mark; it will leak in air from the back end if you do!
12. With minimal delay between steps (a) and (b):
a. Insert the syringe needle all the way into the injection port at the top left of the instrument,
stopping just short of the (very hot!) metal of the injection port guide
b. Depress the syringe plunger completely in one quick, smooth motion, and simultaneously press
the START button on the right side of the GC or in the upper right corner of the integrator.
c. Then extract the syringe needle (for this, there is no rush).
13. Allow elution/integration to continue until the GC automatically ends the run after 2.2 minutes.
14. Repeat steps 9 through 13 again for this same analyte solution.
LET ME RE-EMPHASIZE here that replicate chromatograms for the same substance should look
very similar. If they differ in the number or approximate height of the peaks, you are doing
something wrong, almost surely in how you use the syringe to make your injection. If you get a funny
chromatogram, with too many peaks, do an extra one to make up for it, and don't use the funny one.
If you continually get different chromatograms, contact Rob for help. The syringe might be broken.
15. Repeat steps 9 through 12 again for this same analyte solution. Provided you now have three very
similar looking chromatograms, go on to step 16; otherwise, go back to step 13 and try again.
16. Allow elution/integration to continue until the GC automatically ends the run after 2.2 minutes. In
the meantime, flush the syringe three times with the solvent used for the standard, 40%mass ethanol
in water. This will wash away any of the analytes of interest from the inside of the syringe needle.
17. Repeat steps 9 through 16 for your other two analyte solutions, in turn.
18. You should now have 9 "good" chromatograms, three each for the two whiskeys, and three of your
standard. When you have completed all your runs, press and hold the SHIFT button on the
integrator and then press the ENTER key repeatedly to advance the paper to the next perforation.
Tear off the paper at the perforation and take your integrated chromatograms with you.
19. Please do not turn the integrator or chromatograph off! Leave both of them on! Thanks!
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