We try to setup a used Bruker Avance 200 system. After frequency search we started to setup lock and shim file. Using D2O everithing worked quite well - the spectrometer find the lock and shimming leads to a 1H linewitdth less than 3Hz (10mm tube). Next step we wanted to set the files for acetone-d6. The system finds the lock, but now we see two well shaped lines separated by 0.48 ppm. Shimming does not solve this problem. We also tried acetone-d6 from a different bottle but still see two signals.
Thanks for your comments
asked Nov 17 '10 at 05:47
Hi - you may be seeing the residual acetone-d5 (7 close spaced lines in a multiplet) and H2O (your unexpected peak). Try adding a very small additional amount of H2O and see if the non-coupled resonance increases in intensity. Most solvents contain water, sometimes you can make out two resaonances for "water" - H2O and HOD. Good luck
answered Nov 19 '10 at 00:01