Nuclear Magnetic Resonance (NMR) spectroscopy is a research technique that exploits the magnetic properties of certain atomic nuclei; it determines the content and purity of a sample as well as its molecular structure. Two-dimensional nuclear magnetic resonance spectroscopy (2D NMR) is a set of NMR methods which give data plotted in a space defined by two frequency axes rather than one. 2D NMR spectra provide more information about a molecule than 1D NMR spectra and are especially useful in determining the structure of a molecule, particularly for molecules that are too complicated to work with 1D NMR.
Types of 2D NMR include:
- correlation spectroscopy (COSY)
- nuclearoverhauser effect spectroscopy (NOESY)
- herteronuclear single-quantum correlation spectroscopy (HSQC)
- herteronuclear multiple-bond correlation spectroscopy (HMBC)
- etc.
COSY is the first and most popular 2D NMR experiment, and applied to identify spins which are coupled to each other based on homonuclear through-bond correlation methods. NOESY belongs to through-space correlation methods, which are physically close to each other regardless of whether there is a bond between them. One application of NOESY is in the study of large biomolecules such as in protein NMR, which can often be assigned using sequential walking. Heteronuclear correlation spectroscopy, such as HSQC and HMBC, gives signal based upon coupling between nuclei of two different types. The two methods give similar quality results for small to medium-sized molecules, but HSQC is considered to be superior for larger molecules.
Application of NMR in bio-pharmaceutical areas:
- Structural characterization
- Comparability studies
- Bioprocess validation
- Profiling of impurities and unknowns
- Batch release
- Stability, integrity and fidelity studies
- Process monitoring and metabolic profiling of feedstock
Scientists from Creative Proteomics are professional in NMR spectroscopy, and have methods in place that meet the requirements for the sample test and the recovery method suitability required by USP <761>.
