University:
Purdue University
Course:
CHM 62000 | Spectrochemical Instrumentation
Academic year:

2021
Views:

437

Pages:

4
Author:

Gisselle Blackburn

GAS CHROMATOGRAPH INSTRUCTIONS 1. Turn on the helium gas supply (ridged knob on the gas cylinder). 2. Regulate the gas pressure to 40 PSI (silver handle on the regulator). 3. Check to be sure that the "Detector Power" switch is OFF. 4. Turn the "Current" switch all the way counterclockwise. 5. Switch on the GC main power (Helium MUST be flowing.). 6. Adjust the "Inj. Temp.", "Det. Temp.", and "Col.Temp." to 100 (full scale). 7. After approximately 10 minutes, adjust the operating parameters to the settings below: injector temp set on _____ (135-140 °C) detector temp set on _____ (135-140 °C) column temp set on _____ (115-120 °C) 8. Allow the instrument to warm up until the temperature readings are as indicated above and stable. Use the selector knob to check the temperatures. This step will take 30 - 45 minutes. NOTE: The injector temperature and detector temperature must be 10 -15°C above the column temperature! 9. Turn the selector switch to "Bridge Current". 10. Turn the "Detector Power" switch to ON. 11. Adjust the "Current" control to 100 mA. (Note: The mA scale is the top scale on the display.) 12. Switch on the recorder. 13. Adjust recorder settings: chart speed input "Polarity" 1-2 cm/min 2 mV should be set to provide upscale peaks for the column in use 14. Insert recorder pen. 15. Zero the baseline: Set the "Attenuator" to ∞. Zero the baseline with the "Zero" knob ON THE GC. Set the "Attenuator to 1. Zero the baseline with the "Zero" knob ON THE GC. Return "Attenuator" to operating settings. (Usually 8, 16, or 32 - adjust until peaks are on scale) SHUT-DOWN 1. Turn the "Current" OFF by turning the knob counterclockwise all the way. 2. Turn the "Detector Current" switch OFF. 3. Let the instrument cool for 5 minutes. 4. Turn off the main "Power" switch. 2 5. Open the lid on the GC to cool down the column. 6. Continue gas flow while cooling, and cool for at least 20 minutes! 7. Turn off the helium gas when the column nears room temperature. 3 THE GAS CHROMATOGRAPH OPERATING INSTRUCTIONS 1. Rinse the syringe several times with the sample solution. Allow the solution from the syringe to drop onto a paper towel. You DO NOT need to use water to "clean" the syringe. 2. Pull sample into the syringe: Use 1 ìL for mixtures. Use 0.5 ìL for pure substances 3. Pull plunger back to about 5ìL to add air to the sample. 4. Put the recorder pen in the down position and make the sure chart paper is moving. 5. You will be using Injection Port _____. 6. Insert the needle carefully through the septum in the injector port. (Caution: THE PORT IS HOT!) 7. Inject the sample with a swift, smooth depression of the plunger. 8. Remove the needle from the injector port. 9. On the chromatogram, write down the following information: Attenuator setting Column temp. Sample size Identity of sample 10. Allow time for entire sample to elute before making another injection. 11. Rinse syringe with suitable solvent when finished with the session. 4