主题：[转贴]关于NMR样品管的知识

Broken NMR sample tube in probe

Broken NMR tubes in the probe can cause permanent and/or expensive damage to the probe.

Precautions to avoid breaking a NMR sample tube in the probe are:

Always check the depth of the sample tube in the turbine by measuring sample tube depth.
Before inserting the sample into the probe, ensure the spectrometer is in eject mode and a stream of air is felt at the top of the probe. Will the air flow hold your NMR tube? If not, check the air flow on the flow meters on the magnet leg or contact one of the NMR staff.
Never use old, cracked or chipped NMR sample tubes. Remember NMR tubes should NOT be left in oven to dry for any period of time.
If you suspect that a sample tube has broken in the probe, immediately contact one of the NMR staff. Out of hours ring one of the NMR staff contact phone numbers posted on the notice board.

A sample tube broken in the probe may be detected by a breaking sound when the sample is lowered into the probe or by the inability to eject a sample.

配制样品的步骤:
General Procedure

Because spectrometer time is in very high demand in the Chemistry Department, it is not possible for each student to operate the spectrometer directly. Instead, students will make a proper NMR sample (see below) during laboratory time, submit the sample and the NMR TA will run the sample and return the spectrum and sample. At other times, you will make the NMR sample and make an appointment with the NMR TA during lab time. The student and the NMR TA will meet at the assigned time, and the TA will lead the student through the spectrometer procedure in the NMR room.

Sample Preparation

Proper sample preparation is essential if you want to obtain interpretable spectra. In general, only pure compounds (chromatographed, distilled, or recrystallized) should be submitted for NMR.

1. Use only clean and dry NMR tubes.

2. Use a minimum of 10 mg (preferably 20 to 30 mg) of sample for in approximately 0.5 to 0.75 mL of deuterated solvent for a 1H NMR spectra.

3. Use only deuterated solvents. Deuterochloroform (CDCl3) is the solvent of choice. If a compound does not dissolve in deuterochloroform, see your instructor about using another NMR solvent such as deuterated acetone, dimethylsulfoxide, or water.

4. The NMR tube should be filled to a height of only 3 to 5 cm with deuterated solvent. Overfilling the NMR tube with solvent may dilute the sample too much and wastes expensive deuterated solvents.

5. Suspended solids in the sample lead to a poor spectrum. Solutions containing particulate matter should be filtered before being placed in NMR tubes.

6. Never contaminate the deuterated solvent bottle with any of your compounds.

Procedure 1: Purified sample and dry, acid free deuterochloroform

Place approximately 30 mg of sample in a micro vial. Dissolve your sample in 0.5 ml of CDCl3. Transfer the dissolved sample from the micro vial to an NMR tube using a clean pipette. Using a second clean pipette, add CDCl3 to fill the NMR tube with 3 to 5 cm of solvent.

Procedure 2: Sample with some particulate matter

Dissolve your sample in ~0.5 ml CDCl3 in a micro vial.

1. Put a small plug of cotton in the neck of a short-tip pipette to make a filter; put the pipette in the NMR tube.

2. Using a 2nd pipette withdraw the sample from the micro vial and run it through the filter pipette into the NMR tube. Be careful to not break the top of the NMR tube.

3. Fill the NMR tube to 3 to 5 cm with CDCl3.

Sample Labeling

All sample tubes must be labeled using a string tag. The label should include your name, your sample reference number (initials-notebook #-page #), the suspected structure of your sample, and the deuterated solvent used. Do not use tape to label your tubes.

样品的制备和位置;
相关附件

拿管子还要带手套？没觉得在用洗液清洗啊

ps:那个清洗核磁管内部的小部件估计买不到吧……

我们现在洗核磁管都是先在酸液中泡了，再放到碱液里面泡的，最后用蒸馏水冲洗。一般情况下还是很干净的。但不知道这样是不是对管子损伤很大啊？