Trimethylsilyl propanoate (TMSP or TSP) is a chemical compound containing a trimethylsilyl group. It is used as internal reference in the NMR spectrum nuclear magnetic resonance for aqueous solvents (e.g. D2O). For that usage it is often deuterated (3-(trimethylsilyl)-2,2',3,3'-tetradeuteropropionic acid or TMSP-d4). Other internal references that are frequently used in NMR experiments are DSS (NMR standard) and Tetramethylsilane.
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