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1. Open valve on nitrogen tank to the right of the CD instrument. If the regulator pressure is low or quickly begins to fall from 30 psi, more nitrogen needs to be ordered before the CD can be used.

2. Allow nitrogen to flush through the system for about 20 minutes.

3. Switch ON the lamp power and cooling system breaker (lower right).

4. Wait a few minutes and press the red button (left side of the instrument) to ignite the lamp.

5. Switch ON the cpu and instrument breaker.

6. The IBM computer (right monitor) will start up and ask, “do you want to start the instrument?” Press “y” on the lower keyboard. Wait until it finishes starting up.

7. Turn on the Mac (left monitor) with the lower left hand button; the screen may stay dark for a moment (have patience. It’s difficult to tell if the green ‘on’ light is lit or not).

8. Open the “star MS” icon on the desktop. Answer NO to the message about treating text flow as an error. Wait for the machine to synchronize with the instrument.

9. Answer NO to a message about changing the path from the CD instrument hard drive, unless the path is to another lab group’s folder (then you may want to change it to avoid having to hunt for your files later).

10. Remove the lid to the right of the monitors and lift off the top of the sample holder. Place your cuvette into the slot and replace the top and lid (the slit in the top of the sample holder should be facing you).

11. Star MS will open up an instrument control panel window. Where it reads “monochromator,” it should list the wavelength as 250 nm. Enter the lowest desired value for your scan (i.e. 195 nm) and watch the number in the dynode box. If it changes to 360 nm or above, either start your scan slightly higher (keep checking the dynode for each incremental change) or dilute your sample.

12. Once you have determined the wavelength interval for your scans, enter it in the bottom left of the program window (WL start and stop). Change the monochromator back to 250 nm before beginning your scans. Adjust your sample name, number of scans, and delay interval. Click the ‘run’ button at the top to begin.

13. Once data collection has stopped, you may want to fiddle with it using some of the options under ‘analysis’ on the top toolbar. When you are finished, press the ‘save’ button at the top of the instrument control panel, and your file will be in the CD instrument hard drive icon.

14. When you are finished, remove your sample (tip: don’t lose the cuvette stopper in the machine. It isn’t easy to retrieve). Quit star MS (don’t save the wavelength window or changes to the experiment) and wait for the IBM to switch from the wavelength screen to a prompt. Shut down the Mac and turn off the cpu/instrument breaker.

15. In the logbook, enter your start/stop times and the lamp hours (in the digital box on the left side of the instrument) for your session

16. Turn off the lamp/cooling system breaker and close the nitrogen valve.