Try these parameter sets out if they’re not working for you, we can develop custom parameter sets for you. If you’re editing parameters every time you submit a sample, you’re wasting your time.If you need to enhance weak 1H signals (like end groups on a polymer), use PROTON8, and edit the NS value to something large, like 128 or 256.The parameter set “PROTON32” wasn’t getting much adoption people seem to prefer 8 scans.The pulse sequence used here is different: is uses a 30° excitation instead of 90° don’t touch P1.If NS > 1 is going to be useful for you, use the parameter set PROTON8, which uses 8 scans.And then you need to consider quantitative factors of scan repetition. To increase your S/N by a factor of two, you need to increase NS by a factor of FOUR – that’s an experiment four times as long. Want to make signals appear stronger relative to noise? The effects are limited.Want to improve spectrum resolution? NS > 1 has NO effect – that’s nonfactual lab lore.Want to reduce artifacts from vibration and other noncoherent sources? NS >1 does do that.If you want more scans, please consider what you’re trying to accomplish.One scan with 90° excitation yields plenty of signal, and the long D1 (17sec on 400-1) ensures good integrals. For most regular organic samples, the PROTON1 parameter set works very well.This blog post goes into detail about how the important default 1H 1D parameters are set and why. PROTON1 and PROTON8 use different pulse sequences, and the difference will affect your data. If you want more than one scan, you should use PROTON8, even if you’re going to change the number of scans (NS). Most data can be acquired in one scan (params = PROTON1). After modifying your experiments and just BEFORE “SUBMIT”, under the “Sample preparation” -> “Before first EXP”, click “Lock” pull down list and select “unlocked (alock=u)”, and DESELECT the “Shim”.Everyday 1H NMR spectra should be acquired with default parameter sets that’s the whole point of having them. Now you can create and submit your experiments as usual. When the spectrum linewidth meets your request, type ‘aa’ to exit the shimming. The spectrum will be updated every a few seconds. Hit Z1 with the middle mouse button to change the scale of the variation, left button for decreasing and right button for increasing. Now you can change Z1, Z2 and Z3 values to make the line as narrow as possible. You can expend a part of the spectrum with the mouse in order to see the lineshape more clearly. Go to “Start”, click “Lock scan” -> “Shim” -> “FID scan” -> “Spectrum” as shown in Fig. Select experiment “Proton” as shown in Fig. Go to “Start” -> “Shims” -> click “Read default shims” to load a good shim set. After the tuning finishes, clock “close” to exit the tuning step. 2, click the nuclei you will detect as well as H1 to automatically tune them. Click Tools -> “Tune probe” -> “Autotune probe” as shown in Fig.1. The sample has neither a deuterium solvent nor a strong single H1 peak.īefore shimming, insert the sample and tune the probe first. “Using gradient map xxxx_H1_xxxxx instead of default xxxx_lk_xxxxx”ī. When running gshim, the VnmrJ may display a line like that: On the VnmrJ command line, type “Gmap=’H1’” and hit return. The sample has a strong single H1 peak.Īfter modifying your experiments and just BEFORE “SUBMIT”, under the “Sample preparation” -> “Before first EXP”, click “Lock” pull down list and select “unlocked (alock=u)”, and keep “Shim” selected. If the sample has neither a deuterium solvent nor a strong single H1 peak, you are still able to shim the field with observing the H1 spectrum.įollowing are the steps you should take on Agilent NMR machines.Ī. On the other hand, you can still run a gradient shimming if there is a strong H1 signal, such as water peak. The magnet field may drift during the accumulation, resulted in broad lines. If you have to use samples without deuterium solvent, you are not able to lock the field. Usually the liquid NMR uses deuterium solvent for stabilizing magnet field (lock) and shimming (gradient shimming).
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