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In liquid chromatography, the mobile phase velocity is taken as the exit velocity, that is, the ratio of the flow rate in ml/second to the cross-sectional area of the ‘column-exit flow path.’ For a packed column, the cross-sectional area of the column exit flow path is usually taken as 0.6 times the cross-sectional area of the column.
The theory of high performance liquid chromatography-HPLC is, at its core, the same as general chromatography theory. [41] This theory has been used as the basis for system-suitability tests, as can be seen in the USP Pharmacopeia, [ 42 ] which are a set of quantitative criteria, which test the suitability of the HPLC system to the required ...
Chromatography columns of different types are used in both gas and liquid chromatography: Liquid chromatography: Traditional chromatography columns were made of glass. Modern columns are mostly made of borosilicate glass, acrylic glass or stainless steel. To prevent the stationary phase from leaking out of the column interior a polymer ...
Liquid chromatography as we know it today really got its start in 1969, when the first modern HPLC was designed and marketed as a nucleic acid analyzer. [9] Columns throughout the 1970s were unreliable, pump flow rates were inconsistent, and many biologically active compounds escaped detection by UV and fluorescence detectors. Focus on ...
Liquid chromatography (LC) is a separation technique in which the mobile phase is a liquid. It can be carried out either in a column or a plane. Present day liquid chromatography that generally utilizes very small packing particles and a relatively high pressure is referred to as high-performance liquid chromatography.
In analytical and organic chemistry, elution is the process of extracting one material from another by washing with a solvent: washing of loaded ion-exchange resins to remove captured ions, or eluting proteins or other biopolymers from a gel electrophoresis or chromatography column. In a liquid chromatography experiment, for example, an analyte ...
See also Aqueous normal phase chromatography. It is commonly believed that in HILIC, the mobile phase forms a water-rich layer on the surface of the polar stationary phase vs. the water-deficient mobile phase, creating a liquid/liquid extraction system. The analyte is distributed between these two layers.
Atmospheric pressure chemical ionization chamber cross section. Atmospheric pressure chemical ionization (APCI) is an ionization method used in mass spectrometry which utilizes gas-phase ion-molecule reactions at atmospheric pressure (10 5 Pa), [1] [2] commonly coupled with high-performance liquid chromatography (HPLC). [3]