Chromatography is widely used in various life science applications. Some important applications of chromatography in the food, molecular biology, and forensic sectors are discussed below.
Chromatography can be used in flavor studies and to detect spoilage in foods. Determining the amount of organic acids in foods provides key information about the quality of foods. Column chromatography is used to detect and quantify spoilage indicators such as pyruvic acid in milk. Pyruvic acid content is a measure of psychrotrophic bacteria present in milk.
The same separation method is used to assess total organic acid profile of milk and to measure lactose, which indicates the level of sweetness. Chromatography enables rapid analysis when compared with techniques such as bacterial plating, which may take several days to yield results. Rapid analysis is crucial in the food industry to prevent outbreak of spoilage and to minimize possible health risks.
Additives are added to foods to enhance their flavors or to give them a visual appeal. For example, the presence of added malic acid in apple juice is more difficult to detect because apple juice naturally contains malic acid. However, synthetic malic acid contains fumaric acid as a contaminant and hence its level in an apple juice sample is an indicator of the commercial malic acid. Chromatography has been successfully used to detect and quantify fumaric acid in apple juice.
Determining nutritional quality
Vitamin C depletion in foods can be an indicator of depletion of other nutrients and so the vitamin C content of foods and beverages is closely monitored during all stages of food processing using column chromatography. This analysis can be carried out rapidly using modern acid analysis columns coupled with electrochemical detection even in complex samples. This technique is used to quantitate vitamin C in juices, powdered drinks, and both fresh and frozen vegetables and fruits.
Crime scene testing
Gas chromatography is used to test evidence such as blood or hair from a crime scene. This allows investigators to understand the crime better and to develop theories on what exactly happened and where the victim has been earlier, based on the material found.
Gas chromatography (GC) has been widely used in forensic pathology to identify the type of compounds and fluids present in the human body, post death. This testing can help detect the presence of alcohol or drugs or poisonous substances in the body at the time of death, thus assisting in determining the possible motive and cause of death.
GC is a low cost technique used to identify ignitable / flammable liquids from fire debris. On comparison with a list of flammable liquids publically available, the exact kind of liquid used can be concluded. Mass spectrometry (MS) characterization of the separated components yields better and more precise results.
Molecular biology studies
Hybrid techniques that combine electrochemistry (EC) and MS with chromatography are powerful tools in the study of redox reactions involving various bioorganic molecules. ESI-MS is coupled with liquid chromatography (LC) separation for the characterization of the reaction mixture. EC–LC–MS is applied in the study of biomolecules such as proteins, peptides, and nucleic acids.
Metabolomics and proteomics
EC–LC–MS is essential in mimicking biotransformation reactions, such as phase I oxidative reactions in drug metabolism studies. The technology has been applied in the study of pharmaceutical compounds such as; acetaminophen, diclofenac, lidocaine, clozapine, haloperidol, flunitrazepam, chlorpromazine, alprenolol, albendazole and verapamil.
In proteomics, this technique is used to analyze oxidation of proteins and peptides and in selective labeling of these substances. Chromatography techniques are also widely used in purification of plasma proteins, hormones, monoclonal antibodies, and vaccines as part of their development.
Nucleic acids research
Electrochemistry coupled with LC, MS, or gas chromatography (GC) has been successfully used to identify the oxidation products of nucleobases, nucleotides, and nucleosides. This has accelerated the identification of these compounds compared to long drawn-out isolation steps.