The determination or confirmation of molecular structure for a chemical entity can be performed with a combination of analytical techniques. Some of these techniques are mass spectrometry, NMR spectroscopy, infrared spectroscopy, elemental analysis, and single crystal X-ray diffraction. SSCI is able to combine any or all of these techniques to address complex structural problems. Mass spectrometry and NMR spectroscopy are discussed in more detail below.
Mass spectrometry (MS) is the preferred technique to determine molecular weight and fragmentation data to support the structure elucidation. The use of LC-MS enables one to collect structural data for many components in a complex mixture. Impurities observed using the LC procedure can be further characterized using mass spectrometry. The LC-MS data can be collected using different ionization techniques depending upon the nature of the sample. SSCI can perform LC-MS, LC-MS/MS, and LC-MS/MS/MS analyses using a linear ion trap instrument. The mass spectrometry data can be used for both quantitative and qualitative purposes.
High resolution 1D and 2D NMR spectroscopy can be used to determine the atomic connectivity and structural conformation of molecules in solution. Both 1H and 13C NMR spectroscopy provide detailed information about molecules. Various 2D proton NMR correlation experiments such and COSY, TOCSY, and NOESY enable one to determine the relative locations of protons or the conformation of a molecule in solution. Additional 2D proton-carbon NMR correlation experiments such and HMQC, HSQC, and HMBC can be used to connect the carbon backbone of complex molecules. These NMR techniques are used to determine the assignments of all resonances for a molecule, and knowledge of the relative position of each nucleus permits the determination of the molecular conformation in solution. SSCI can perform variable temperature, multinuclear, and gradient selected NMR analyses. Quantitative and qualitative data can be obtained using NMR spectroscopy.
SSCI can perform these structural analyses under cGMP conditions.