HPLC (High Performance Liquid Chromatography) is a technique to efficiently and accurately separate and quantify many soluble compounds in plants by using a pump, column, autosampler, and detector. Most phytochemicals compounds are soluble to polar or non-polar solvents and can be extracted by using a proper solvent, and can be analyzed by using an HPLC system.
The HPLC systems are fully automated and can analyze many samples without supervision.The VFIC lab, has eight units of HPLC systems and each unit is assigned to a compound for an efficient analysis and minimal maintenance. However, a new setting can be done for a new compound analysis. There is a stock of different columns and detectors for the analysis of various compounds in fruits and vegetables. The compounds being tested include sugars, carotenoids, flavonoids, limonoids, phenolic, amino acids, cynarin, capsaicins, pyruvic acid, vitamin C, and total phenolic. Additional compounds will be analyzed when necessary.
Our research in the HPLC lab is closely linked to the Analysis lab works. Most phytochemical extractions will require an HPLC analysis. Scientists utilize specific columns, composition and solvents for the most optimum condition of the analysis. Some compounds are similar in chemical or physical properties which makes it difficult separate each compound. Then, various techniques are used to efficiently separate and quantify them. Scientists usually begin with by adopting a method published earlier but some modification and optimization are common for better and more efficient analysis.
We are routinely analyzing many compounds listed above for our Center projects. Samples are coming from our own research projects and from our collaborators located throughout Texas and other states. Currently, we are testing ascorbic acid, quercetin, luteolin, and capsaicins in various pepper germplasm peppers and amino acids in onions. As a new project we are investigating cynarin in artichoke. Systems to measure total phenolic or DPPH are under development for a fast and accurate analysis.