Development trend of high performance liquid chromatography packing technology
High performance liquid chromatography (HPLC) is a modern separation and analysis method. Since the 1960s, as an analytical technique, HPLC has been widely used in life science, environmental science, pharmaceutical analysis and other fields. Among them, chromatographic packing is the core of chromatographic technology. It is not only the foundation of chromatographic method, but also an important consumable. As the carrier of chromatographic packing, chromatographic column is well known as the “heart” of chromatograph. High performance liquid chromatography packing has always been one of the rich, dynamic and creative research directions in chromatographic research.
Because of its excellent chromatographic performance, silica gel-based chromatographic fillers are widely used as liquid chromatography fillers, especially for the separation and analysis of small organic molecules, silica gel-based chromatographic fillers occupy the majority of the market share. In recent years, exciting developments in this field have been based on the development of rapid liquid phase technology in two directions.
1. Super high performance liquid chromatography (UHPLC) packing technology
Since Waters launched UPLC instrument in 2004, ultra-high performance liquid chromatography (UHPC) technology has been widely used for its advantages of high speed, high separation and high sensitivity. The core of this technology is based on the chromatographic packing of 2 m small particle size silica gel. When the packing particle is less than 2 m, not only the column efficiency is obviously improved, but also the separation efficiency does not decrease with the increase of flow rate. The separation velocity and peak capacity can be extended to a new limit by using high flow rate, but the column pressure also increases significantly. Ultra-high performance liquid chromatography (UHPC) system with higher pressure is needed for small size fillers, and the production process of chromatographic columns is also required to meet higher requirements. At present, in addition to the well-known international chromatographic instruments and column companies (such as Waters, Agilent, Phenomenex) to produce UHPLC column, domestic chromatographic column manufacturers have also introduced such products. Although UHPLC instruments are still the monopoly of international famous brands, domestic UHPLC columns can replace imported brands.
2. Core-shell chromatography packing
Core-shell packing is a new type of chromatographic packing developed by Jack Kirkland in 2006. It is prepared by melting the porous silicon shell onto the solid silicon core surface. These porous “halo” particles have very narrow particle size distribution and diffusion path, can reduce both axial and vertical diffusion, allowing the use of shorter chromatographic columns and higher flow rates to achieve rapid and high resolution separation. Moreover, the back pressure produced by core-shell column is lower than that of UHPLC column. Low back pressure can reduce the pressure of the instrument, which makes it possible to achieve the separation effect of ultra-high performance liquid chromatograph on conventional liquid chromatograph. However, the core-shell chromatographic column is not suitable for large-scale preparation of liquid chromatography because of its high requirement for the dead volume outside the column and its capacity is smaller than that of the full-porous packing.