HPLC, Breaking Though Traditional Barriers
High Performance Liquid Chromatography (HPLC) is an important chromatographic technique based on the separation of molecules because of the differences in their structure and composition. The separation technique depends upon the overall interactive relationships between analyte, mobile phase, and stationary phase. It is generally improved form of column chromatography and offers safest, fastest, automated, and accurate method for identification of certain components in a sample.
Column switching. If the flow through sequence is branched and switching devices are employed to interface individual columns, exerting powerful control on the quality and the basis for the separation, this versatile nature makes liquid chromatography a powerful separation system. It leads to the idea of column switching, means that the carrier flow is changed by standard six-port high pressure valves, as a result a fraction of or all of the effluent from any column (primary) is transferred to other column (secondary) forming a network for further separation.
In modern liquid chromatographic techniques, the term column switching is used for different operating modes in a strictly non-defined sense. Column switching can also be synonymously expressed as sequential chromatography, coupled-column chromatography, multi-channel chromatography, multiple chromatography, split chromatography, but they are used with different objectives for chromatographic separations. Multi-dimensional liquid chromatography. It provides multiple dimensions based upon different separation mechanism having sufficient resolving power for the separation of complex mixture in food analysis, molecular biology, metabolomics and proteomics.
Micro-column and nano-liquid chromatography. For carrying out technological, theoretical, and methodological studies, especially in the field of analytical chemistry miniaturization of liquid chromatographic instrument is done. This provides shorter analysis time due to lower flow rates, better separation efficiencies and successive coupling with MS.
Chip-based liquid chromatography. Micro-fabricated devices (named μ-total analysis system, μ-TAS) are used for analyzing minute samples in the shortest possible time and integrating in the same instrument both pretreatment of the sample and separation. The main advantages of these devices are the low LODs (Limit of detection), increased sample loading and peak capacity and the minimization of handling and transfer steps they offer.
Ultra-performance liquid chromatography (UPLC). It is new direction of liquid chromatography. UPLC technique has made progress in particle chemistry performance, detector design, system optimization, data processing and control.
