FAQ

Ideally, the sample is dissolved in a 5mm NMR tube (with 7" or 8" length) in one of the common deuterated solvents. The optimal volume is 600-700µl. Too much solvent will affect the shimming of the sample which can lead to unwanted line broadening or peak deformation. The unnecessary amount of solvent will dilute the sample and affect sensitivity. Too little solvent has similar problems with shimming, and the incomplete coverage of the spools in the probehead also affects the sensitivity of the measurement.
For small organic substances (MW < 300), the amount of dissolved substance for ¹H spectra should not be less than 1 mg. ¹³C spectra require much longer measurement times due to the much lower natural abundance and the amount of substance should therefore not be less than 20 mg (dry mass of pure compound). Less concentrated samples for ¹³C spectra can be measured overnight or over the weekend after consultation and depending on the availability of measuring time.
Special requests can be noted on the sample delivery slip. As the spectra are normally interpreted and processed on the PC nowadays, no paper printout of the spectra is made!
When preparing the sample solution, make sure that the solution is homogeneous and clear! A mixture of deuterated solvents should be avoided if possible. If this is not possible, one of the two solvents should be present in clear excess.
Caution: To ensure the safety of the persons recording the spectra, it is very important that the sample containers are clean on the outside! If the tube or the delivery slip are contaminated, the samples will be returned unmeasured.

Samples can be handed in 24/7 in the designated area in front of our department. However, direct processing only takes place on working days, Monday to Thursday between 0730 and 1500 and Friday from 0730 to 1400. It is highly recommended that samples are handed in within this time window to ensure prompt processing.

In routine operation 1D spectra of 1H, 13C, 31P, 19F, 29Si as well as 2D spectra COSY(H,H), HSQC(H,C), HMBC(H,C) & NOESY (H,H) at standard conditions at 300MHz are offered. Measurements away from room temperature, other field strengths, time courses etc. must be agreed in advance by appointment!

All data are available for self-download. Please ask for the IP address and login data in your working group (from the respective NMR representative) or directly from the NMR department. We ask for your understanding that in the current situation no access data will be posted publicly. Users are responsible for downloading their data promptly.

An attempt is made to process the samples as quickly as possible. However, it cannot always be guaranteed that samples will be measured in the order in which they arrive. This may vary depending on the spectra required and the availability of equipment.

The reason for the problem is usually stated on the sample slip. However, the most common problems are that essential information is missing on the sample slip, no deuterated solvent was used or the sample (and/or the slip) does not meet the specifications for cleanliness.

For those interested outside the Institute of Chemistry, there is the possibility to have measurements carried out for a fee. In principle, it is possible to use standard experiments as well as to develop more complex solutions.

If you are interested, please contact Prof. Dr. Klaus Zangger.