Quantitative Phosphorus NMR (Quant 31P NMR)
Quantitative phosphorus NMR identifies the major phospholipid classes and their degradants in a sample and gives quantitative results in terms of weight percent or concentration of a phospholipid solution. Since most phospholipid classes contain a single phosphorus atom, a single, resolved peak per class is observed in the 31P NMR spectrum. Once each phospholipid is identified in a sample, a standard of known concentration is used to determine the concentration of each identified phospholipid using the direct relationship between peak area and the molar response of each phospholipid. We commonly use this method to identify and determine the amount of phospholipids in raw material extracts, nutraceutical supplements, and phospholipid mixtures.
Qualitative Phosphorus NMR (31P NMR)
This is a quick and reliable method for identifying the phospholipids present in a sample by comparing the chemical shifts in the 31P NMR spectrum to the chemical shifts of known phospholipid standards. These results will be reported for identification purposes only, and not to provide quantitation of each phospholipid species present. This option may be useful for confirming the identity of a phospholipid raw material or extract, if the quantitative data is not necessary.
Proton NMR is a method used for the structural characterization and identification of a sample. Only a few milligrams of sample is needed for analysis. Characterization is accomplished by identifying each hydrogen atom within a molecule based on its chemical shift in the 1H NMR spectrum relative to an internal standard (tetramethylsilane), peak splitting, and peak integration.
Carbon NMR is also useful for structural characterization, especially when used in addition to proton NMR for identification of a sample. More sample is required for this analysis (at least 50 mg). Each carbon within a molecule has a specific chemical shift in the 13C NMR spectrum relative to the internal standard, tetramethylsilane, and can be identified. This method can also be particularly useful in determining the presence of isomers within a sample.
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Please note that all of Avanti Analytical Services are performed in a Quality Control Laboratory by a trained analyst and is intended for research use only. All work is documented and reviewed by a second trained analyst but does not involve the review of the cGMP Quality Unit of Avanti. If you require cGMP analysis of a sample, please see our cGMP Testing Services page for more information.