Design of HPLC Column End-fittings with Integrated
Publication Date: 2016-Mar-03
The IP.com Prior Art Database
DESIGN OF HPLC END-FITTINGS WITH INTEGRATED CAPILLARIES
This article discloses a new design for the end-fittings of high-performance liquid chromatography (HPLC) columns.
HPLC refers to a class of techniques of analytical separation in which a fluidic mobile phase, typically consisting of one or more aqueous and/or organic solvents, carrying a sample under investigation is driven through a column under high pressure. A typical HPLC column is packed with a material, often in the form of particles such as silica beads, which serves as a stationary phase. The stationary phase is packed between two axially opposing frits in the column that have openings to allow the mobile phase/sample to flow through the stationary phase in the general direction from the inlet end to the outlet end of the column, while retaining the stationary phase in place between the frits. The particles of the stationary phase are configured (e.g., sized and formulated/functionalized) to provide chromatographic activity. That is, different components (e.g., chemical compounds) of the sample will be retained on (or have affinity for) the stationary phase to different degrees, and thus will pass through the column at different flow rates. Consequently, the different components become separated from each other in the column and ultimately exit the column in sequence. Components of the same type thus exit the column together as a detectable “band” in the mobile phase. Temporally separated bands flow from the column to a suitable detector. The detector measures or detects the bands and provides a signal output from which a chromatogram can be constructed. The chromatogram may, for example, plot signal intensity as a function of retention time or retention volume, thereby presenting peaks corresponding to the different bands (and hence the different components) detected/measured.
An HPLC column commonly contains end-fittings at the axially opposing inlet end and outlet end of the column. The end-fittings seal the stationary phase media inside the column and contain threaded connections for capillaries that are to be joined to the inlet end and outlet end. These capillaries respectively connect the inlet end to an HPLC pump and the outlet end to the detector. A typical column is illustrated in Figure 1 and described further below. The end user of an HPLC system is expected to be able to make and break these threaded capillary connections when installing the column on the system and when making any changes to the system’s set-up. The quality of the connection, including the sealing of the capillary to the end-fitting and how well the capillary is seated, will affect the performance of the system. Failure to properly seat the capillary can cause loss of plates (the number of “theoretical plates” being a well-known measure of chromatographic performance), peak shape distortions, leakage, and sample carry-ov...