by Chromatography refers to a set of laboratory techniques used to separate the components or solutes of a mixture based on their interactions with a two-phase system. One of the phases is stationary while the other (known as the mobile phase) moves in a definite direction relative to the stationary phase. The difference in the rate at which the components interact with and distribute themselves between the two phases leads to their separation. The process enables the qualitative and quantitative analysis of each component in a mixture.
Types
Based on the nature of the mobile and stationary phases, there are several major types of its techniques:
Gas chromatography (GC): In GC, the mobile phase is a gas like helium or hydrogen while the stationary phase is a liquid coated on an inert solid support packed into a narrow tube called a column. It is used to separate and analyze volatile compounds that can be vaporized without decomposition.
Liquid chromatography (LC): In LC, the mobile phase is a liquid like water or organic solvent while the stationary phase is a solid support similar to GC. However, LC is used to separate compounds which are either thermally liable or non-volatile. It has two major modes – normal phase LC and reverse phase LC based on the polarity of the mobile and stationary phases.
Ion-exchange: Here, the stationary phase contains ionizable groups that can exchange or release ions in solution. It is used to separate and purified ions and polar molecules based on their affinity to the ion exchanger groups.
Size-exclusion: Also known as gel permeation chromatography, it separates molecules based on their size or molecular weight. The stationary phase contains porous beads or gel matrix which allows differential passage of molecules based on their size.
Affinity chromatography: It utilizes the specific non-covalent binding interactions between a substance and immobilized ligand to separate target biomolecules from a complex sample.
Applications
They finds extensive applications in diverse fields due to its high resolving power and selectivity. Some major areas where it is employed are:
Pharmaceutical analysis: It is the primary technique used for quantitative analysis and separation of drug substances, excipients, impurities, degradation products and metabolites in biological samples. It ensures drug quality, safety and efficacy.
Food and flavor analysis: It helps identify, quantify and purify food components, flavors, preservatives, contaminants, toxins, etc. GC is commonly used to analyze volatile compounds in foods.
Environmental analysis: Chromatographic methods play a vital role in monitoring and quantifying environment pollutants in air, water and soil. It detects trace organic impurities, pesticides and their metabolites.
Biomolecular analysis: Techniques like LC, GC, affinity they are utilized in proteomics, metabolomics and glycomics research for separation, identification and quantification of biomolecules.
Forensic analysis: They are coupled with mass spectrometry helps in identification and analysis of controlled substances, explosives, poisons, arson residues, inks and dyes in forensic caseworks.
Instrumentation
The basic modules required for it include:
– A sample injection port to introduce the test mixture
– A chromatographic column packed with stationary phase
– A detector to sense and quantify the separated analytes/components
– A data station to record and process the detector signals
– Pumps to deliver the mobile phase at defined flow rates
Some common detectors used are flame ionization detector (FID) in GC, UV/visible, refractive index (RI), evaporative light scattering (ELS) for LC. For additional structural information, it can be interfaced with mass spectrometry (GC-MS, LC-MS).
Modern instruments are computer controlled with auto-samplers, auto-calibration and advanced separation columns for high throughput analysis. Multi-dimensional chromatography further enhances resolution of complex samples.
Advantages
– High resolution separation of similar compounds not possible by other techniques
– Automated analysis of a wide range of samples – large, small, volatile, non-volatile, ionic, biomolecules, etc.
– Provides both qualitative and quantitative analysis capabilities
– Coupled with MS for unequivocal identification of unknown compounds
– Versatile technique suited for diverse fields and applications
– Continues to evolve with novel stationary/mobile phases, dimensionalities, detection modes
chromatography is a vital analytical technique that has revolutionized separation sciences. It has enabled detailed characterization and analysis of chemical and biological systems that would have been otherwise difficult or impossible. Advancements in instrumentation will further strengthen its role in research, industries and other areas.
*Note:
1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it
About Author - Priya Pandey
Priya Pandey is a dynamic and passionate editor with over three years of expertise in content editing and proofreading. Holding a bachelor's degree in biotechnology, Priya has a knack for making the content engaging. Her diverse portfolio includes editing documents across different industries, including food and beverages, information and technology, healthcare, chemical and materials, etc. Priya's meticulous attention to detail and commitment to excellence make her an invaluable asset in the world of content creation and refinement. LinkedIn Profile
