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On our Avance III 500 we use Topshim quite successfully for any probe with a gradient coil. The only time we have a problem is with CDCl3 solvent on our 1.7 mm TXI probe, where Topshim fails with a complaint about the signal to noise ratio being too low. This is not surprising for a microprobe, as CDCl3 has the lowest signal of any common deuterated solvent. We have confirmed that the 2H pulse length is correct in the prosol file. An obvious solution would be to increase the nunber of scans for this probe/solvent combination. There seem to be probe and solvent specific parameter files in the topshim folder (under ..\conf\instr). I have tried making some changes to these files in the obvious places, but the number of scans used always seems to remain at the default (4 for 2H). Does anyone know how to do this properly? Clemens, I'm looking at you :-) Thanks -Kirk |
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Hi Kirk, It is not in the manual. I apologize. My colleague Dr. Krull reminds me to use: topshim durmax=30 (the default is 15). This is for the total time that topshim will signal avg, not necessarily the ns. but maybe this will work. Let us know! If not I'm sure Clemens will see this. Good luck, Bernie PS: Try only ordmax=3...so "topshim rga ordmax=3 durmax=30" in command line. Bernie: O.K. This seems to work. Thanks -Kirk - Kirk Marat (Aug 09 '11 at 12:23) For 1.7 mm, I think ORDMAX=4 would be O.K. as well - Kirk Marat (Aug 09 '11 at 12:26) Glad to hear this worked...ordmax=4 may also work, correct. Best regards, Bernie. - bernie o'hare (Aug 14 '11 at 07:52) |
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Hi Kirk, The way to do this is in the topshim manual (found electronically under the help tab). I will find the command and comment later when I have access to my pc. Also, try topshim rga. This may also help. I will comment again soon. Bernie Bernie: I have tried the method described in section 4.5.3 of the manual. NS does not seem to be a parameter in default.par, and if you create a parameter file "myfile.par" (as suggessted in manual) with only NS , you get an error like: "no parameters of class in file". Thanks -Kirk - Kirk Marat (Aug 08 '11 at 09:34) |
