1. The homonuclear decoupling board is only present on the Gemini 200 in room 38, building 65. Do not use this procedure elsewhere. The configuration system has been set with Homodecoupler to YES which indicates the homodecoupling board is present. 2. If it is the first time you are using this application it is best to select a simple molecule to practice the following steps. The ethylbenzene reference standard has a quartet and triplet that are initially easier to work with than your research compounds. An example spectra of the ethylbenzene decoupling is shown at the end of this page.. 3. Tune the probe and run a normal spectrum, without selecting the decoupling mode, e.g. with DM=NNN 4. There are two macros which are one-step commands to switch back and forth between normal and decoupled spectra. They are DECouple on and off: DECON which sets DM=Y and HOMO=Y DECOFF which sets DM=N and HOMO=N 5. After obtaining a normal (GA), either use DCR or F3 to display a cursor. Place the cursor exactly over the center of the multiple peaks, type SD, and select a value for DLP. After entering SD will see a value such as D0 = -494.6(2.89ppm) 6. For a 1H spectra the best value for DLP is found experimentally. The values of Decoupler Low Power control range from 2047 to 0. Too much power may show increased noise and too little power will not decouple the peaks. DLP=1600 is a good starting point. Type DLP=1600 then GA. When decoupling takes place a vertical line appears at the cursor and the ethylbenzene triplet becomes a singlet. Do Not exceed DLP of 2000. 7. After completion of the decoupling do not forget to turn DEC off with the macro DECOFF. Check to make certain the decoupling mode is turned off when you leave the instrument either with DG or DEC?
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