CHIRAL CHROMATOGRAPHY

Chiral chromatography is a revolutionary analytical method used extensively in the initial stages of medicine development. This is done through the chromatography process and other related techniques. In the field of biology and pharmaceuticals, it is used to serve the interest of compound analysis. It is the best process of separating “enantiomers”. “enantiomers” are basically “chiral” particles that are similar to each other and non-superimposable.

Instrumentation and components of HPLC

The term ““chirality” is in focus and the main concept. “chirality” is the study of three-dimensional molecular structure. The term “chiral’ comes from the Greek word chirthat means handedness. “chiral” molecules tend to show right and left-handed nature. “chiral” chromatography is the subject of analytical and modern chemistry and fermentation technology.There are two major types of detectors used in HPLC – selective detectors (solute property)and universal detectors (bulk properties). An HPLC instrument consists of nine elements – solvent container, column, post column, sample introduction device, column, post column, data collection, output system and connecting tubing. There are innumerable ways through which separation of isomers and “enantiomers” can be carried out. The separation of “chiral” molecules is in great interest in fermentation technology because most of the molecules are chiral. Examples of chiral bio molecules will be nucleic acids, protein, amino acids and sugars. In nature, chiral molecules are present in two possible forms such as amino acids in L-form and sugars in D-form. Because of chirality living beings show different biological reactions to a set of enantiomers which is present in waste materials, pesticides, and medicines. Chirality has become a major issue for the modern pharmaceutical industry. Living bodies are selectively chiral and tend to interact with each racemic medicine individually and metabolize each enantiomer through a completely different way and produce pharmacological compounds. Thus, one isomer is capable of producing desired therapeutic activities, on the other hand, other isomers may become inactive and produce unwanted effects.

Chiral molecules and recognition of enantiomers are the basic terminology used in biological sciences. The perpetual nature of living beings has substantial effects on biologically active elements with which they may interact. Biological structures are sensitive to chiral molecules and different responses have been observed when dealing with different pairs of enantiomers.  Polysaccharide derivatives represent the most versatile group of “chiral” selectors for liquid phase segregation of “enantiomers”. These are certain groups of “chiral” analysts that have been reported to demonstrate the inadequate “chiral” detection capabilities of these “chiral” selectors.

Small anaerobic carboxylic acids belong to this class of “chiral” compounds. Thus, these analyzers are usually converted into different derivatives before segregating their “enantiomers” into polysaccharide based “chiral” columns. Analysts do offer some advantages from the point of view of derivative separation and detection. There are also disadvantages such as an additional synthetic step before segregation. There is a possibility of incomplete derivatization, residual derivation, the segregation process, and additional costs. Additionally, if the analyzer is needed in its enantiomerically pure form after the segregation, an additional step will be needed to restore the analyzer to its initial form from its derivatives used in the separation process which may be understood by extra errors.   

The primary five components of the HPLC system involve a solvent container, column, high-pressure pump, injector system, and detector. There are two types of chromatographic methods such as direct and indirect chromatographic methods. The principality of “chiral Derivative Agent (CDA”) is used to produce diastereomeric pairs with relevant segregation and detection possibilities was the first method extensively used for enantiomeric separation of optically active molecules in liquid chromatography. Direct chromatography methods were carried out through six ways as “Chiral Mobile Phase Additives (CMAs)”, “chiral” stationary phases, Pirkle phases, CSPs based on polysaccharides, cavity phases, and macro cyclic antibiotic phases. 

Instrumentation of chiral chromatography

“Chiral” chromatography is the alternative method of column chromatography. There are two types of detectors used in HPLC that are available for detecting chiral molecules through two options – Optical rotation (OR) and circular dichroism detector (CD). One example of a chiral molecule could be glucose, amino acid except glycerin protein, DNA, lactose, maltose, and sucrose. “chiral” chromatography deals with a mobile phase e.g., gas or liquid through a “chiral” stationary phase in a cylindrical structure fundamentally a thin tube. The analyte sample is injected into the mobile phase. The two “enantiomers” have different relationships for “chiral” stationary phases. As “enantiomers” reach an equilibrium state among stationary and mobile phases the more strongly bound “enantiomers” will take advantage of more time to bind to the stationary phase. Hence, it will appear later from the column.

Conclusion

Originally, chromatographic techniques were used to segregate molecules based on their color. Over time its range of applications has substantially expanded. Today, “chiral” chromatography is considered an extremely sensitive and efficient segregation method. These days, “chiral” chromatography has been substantially used for separating optical isomers and “enantiomers”. Isomers are not molecules that share the same physical or chemical structure or superimposed with each other but have similar formulas. On the other hand, “enantiomers” have different formulas but have similar physical or chemical structures and can be superimposed.