I know I should use HPLC with chiral stationary phase but I wanna know more about other analysis
Your question is somewhat broad and I would suggest you first spend some time on your own using a keyword search on the web. This may help you refine your real question or better direct your efforts.
A few comments:
First, an achiral analysis of the compound would need to be performed to determine its analytical purity in the mixture.
- Most drug compounds include many other inactive ingredients which may interfere with any analytical analysis of the chiral component. It helps to know ahead of time what specific compounds you need to resolve BEFORE you start.
The chemical purity method development step is a very important first step. Any chiral analysis technique or method used next, to resolve the racemic standard, would only be as good as the chemical purity of the sample. So, if your chiral racemate or true enantiomer(s) are not pure, the data obtained from any chiral analysis may not be accurate or valid. *Chiral columns are very poor in selectivity so co-elution of 'other' compounds in the sample is a common problem and why a great deal of professional expertise is required to perform chiral method development/analysis.
Multiple chromatography modes provides a route to determine chiral purity. In some cases, derivatization with GC analysis may be performed. Capillary electrophoresis may also be an option. HPLC and optionally, SFC (SFC is more limited in range and type of samples than NP or RP chiral HPLC) are the most popular techniques. Your specific sample type and your analysis goals (i.e. do you need to collect fractions, run large quanties of sample etc) will determine which techniques are most appropriate to try.
Other than chiral LC separation which is the forefront technique, circular dichroism is an option based on detection differentiation. It is a kind of active detector to separate the enantiomeric structures in a solution.
Circular dichroism (CD) and also Faraday type detectors detection would only be applicable for a chirally pure compound (or separated peak), not a mixture of compounds or different drugs. CD also has poor sensitivity for some compounds so you would need to have a large enough sample to get a signal.
Agree with William Letter,
You need to isolate the target chromatographically (do not need to separate -S and -R) and use CD to elucidate the racemic composition...
Under constant conditions, a deviation in the g-factor for a sample with respect to the value for a pure enantiomer indicates the presence of a chiral impurity.
Here are the links for clarification;
https://jascoinc.com/wp-content/uploads/2018/10/The-Use-of-Circular-Dichroism-Detection-in-SFC-to-Determine-Enantiomeric-Ratios-without-Peak-Resolution-Vertical.pdf
Article Enantiomeric Impurity Analysis using Circular Dichroism Spec...
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