Circular Dichroism Protocol

Protocol for AVIV Model 202 Series Circular Dichroism Spectrometer in Rm 9 Schlundt Annex

Turn On The Machine:

1. Check the nitrogen tank, if the middle of the white float is below the bottom line, add some N2 from Chem Stores (in Chemistry building) for safe operation. (30 liters of N2 can last for about a 12 hour experiment)

2. Check the oxygen scrubbers behind the machine; make sure they are open.

3. Check the inline oxygen indication, it should be dark not tan.

4. Turn on the nitrogen with green knob, adjust pressure to ~12psi, note the float is close to arrows on the front panel.

5. Turn on the power to lamp & cooling, wait for ready light, then hit "push to start" to fire the xeron lamp. Lamp current will indicate the lamp is on.

6. Turn on the power to computer & instrument.

7. Sign into the logbook.

Measurement:

1. The cuvettes are owned by the Beamer, Quinn, and Van Doren Labs. Please see them for permission to use. Wash the cuvettes with water and ethanol before use. After use, wash them again and fill with water or ethanol.

2. Add your sample to the cuvettes (filter your sample whenever possible), and place into the rotor.

3. Open the AVIV Program, set your count # and rotor position, begin experiment. Go to correct drop-down menu to set up your parameters (wavelength scan or melting curve), the software manual is available beside the machine for your reference. If you do a melting curve, it will take a very long time (>12 hours), and the temperature will rise very slowly once it's over 70 Celsius. (Sometimes it won't go above 90 Celsius)

4. Once experiment is done, you should remove your data from the default folder to your own folder. You can print data at once. It is possible to view your data on another computer using a copy of the AVIV Program.

Turn off the machine:

1. Log the number of total hours operation after use in the logbook.

2. Turn off power to lamp & cooling system.

3. Turn off nitrogen.

4. Exit AVIV program and shutdown Microsoft Windows.

5. Turn off power to computer & instrument.