Sample Introduction -- The sample tube must be correctly positioned in the spinner turbine. Insert the sample with the head of the turbine (spinner) up, as shown at the right. The solution should be approximately centered about the receiver coil area and should extend a fair amount above and below the coil. Under no circumstances should the tube extend below the probe bottom. There are several guides in the lab to help in positioning the tube. The spinner should be wiped clean before putting it in the magnet.
Caution: Most costly damage to NMR spectrometers occurs before and during sample insertion.
1. Always use the paper gauge on the right leg of the magnet to correctly position the sample tube. When the sample tube is extended below the safe level it will break in the probe and cause damage to the probe. If the tube is not extended far enough it may not be possible to obtain a good lock signal. See the following Sample Depth gauge.
2. This is where you are most likely to hurt the instrument. The eject air must support the turbine with sample tube before you let go of it. Use utmost care during this procedure. The turbine with positioned tube are allowed to rest on the air cushion at the top of the upper bore tube of the magnet. The support-air flow will be first reduced for lowering and then turned off altogether. Shortly after you hear the turbine set down, you should hear a relay click turning on the spinner air and the spin indicator should light on the leg of the magnet. What If my tube broke when I inserted it into the magnet
During the day, phone a staff member. Tell them the solvent and any hazards posed by your compound.
After normal working hours leave a note to warn others not to use the instrument. The more quickly you lower a tube into the magnet, the more likely it is to break! If necessary, use two hands on the sample eject button to make it easier to lower the tube slowly.
More Caution: Attempting to observe a nucleus with the wrong probe or with an improperly tuned probe can damage the electronics. Attempting to insert a 10 mm tube in a 5 mm probe will also produce damage.
