Apparatus for direct addition of reagents into a nuclear magnetic resonance (NMR) sample in the NMR probe

Nuclear magnetic resonance (NMR) is a widely used tool in chemistry and bio chemistry. It is occasionally necessary to add small aliquots of solvents o r reagents repeatedly into the NMR tube. Ordinarily this is accomplished on ly by ejecting the sample and carrying out the addition outside the probe. It would be preferable to add the aliquot directly into the sample. We have designed and implemented a delivery system to accomplish this. This appara tus is particularly applicable to a recent NMR titration method for measuri ng relative pK's and to experiments where temperature must also be varied. This apparatus provides a safe, simple, and inexpensive method for repeated aliquot addition directly into the sample in the NMR probe. (C) 1999 Ameri can Institute of Physics. [S0034-6748(99)01504-X].