Enantiomeric excess (ee) is a measure of the difference in the amount of two enantiomers (mirror image molecules) present in a sample. It is expressed as a percentage and represents the excess of one enantiomer over the other.
Enantiomeric excess is important in determining the purity and quality of a sample. It is particularly relevant in the pharmaceutical industry, where only one enantiomer of a drug may have the desired therapeutic effects while the other may have adverse effects.
A 400MHz 1H NMR instrument uses nuclear magnetic resonance spectroscopy to detect the presence of different enantiomers in a sample. The instrument measures the energy absorbed by the molecules as they interact with a strong magnetic field and radio frequency pulses, providing information about the molecular structure and composition of the sample.
The high sensitivity and resolution of a 400MHz 1H NMR instrument allow for accurate and precise measurement of enantiomeric excess. It can also be used for a wide range of sample sizes and types, making it a versatile tool for enantiomeric analysis.
One limitation of using a 400MHz 1H NMR instrument is that it may not be able to detect enantiomeric excess in very small or dilute samples. Additionally, it may not be able to distinguish between enantiomers with similar chemical shifts, making it important to use other analytical techniques in combination for accurate results.