Suppose I have a pure compound composed of 50% of R and 50% of S enantiomers and I will prepare a solution of this compound of 100mg/L. Does the solution contain 50 mg/L of S enantiomer and 50mg/L of R enantiomer?
Racemates are expected to be equimolecular mixture of both R and S enatiomers and solution prepared of such a racemic mixture consists of equal amounts of enatiomers. While calculatiing the compound concentration you have to consider the molecular weight of the racemate compund
If it is a racemic mixture, it is expected to have the same amount of each enantiomer, in your case it would be 50mg/mL of each.
You should also consider whether there can be interconversion between the two isomers when in solution. Typically, even if there is interconversion, neither isomer is envergenically favored, so the equilibrium concentration should be 50:50. But some circumstances could favor one isomer over the other.
If ur racemic mixture that time R and S enantiomers are same amount and for calculations of concentration of enantiomers you can consider molecular weight of the both enantiomers i.e R and S
I have a chiral column and I can see both peaks R and S, that is OK. But I am not able to calibrate each enantiomer, because the standard is racemic mixture of my compound. That is why I asked if I do it right... Finally I have calibration for both enantiomers, I just need to divide by two the concentration of the individual calibration standard in the case of R or S enantiomer....
If a compound consists of a mixture of R and S enantiomers and you want to calculate its concentration, you need to use the concept of enantiomeric excess (ee), which is a measure of the degree of asymmetry in a mixture of enantiomers. Here's how to calculate the concentration of a compound with a known enantiomeric excess:
ee = (larger amount - smaller amount) / total amount
[R] = (total amount * ee) / total volume [S] = (total amount * (1 - ee)) / total volume
where [R] is the concentration of the R enantiomer and [S] is the concentration of the S enantiomer.
Note that if the compound has a racemic mixture (i.e., a 50:50 mixture of R and S enantiomers), then the ee value is zero, and the concentration of each enantiomer is equal.
Also, keep in mind that different analytical methods may have different sensitivities to each enantiomer. So, depending on the purpose of your analysis, you may need to use a chiral chromatography column or other specialized techniques that can separate enantiomers.
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