The empty HPLC column is assembled from column joints, column tubes, and filters.
The HPLC columns joints are constructed with a low dead volume. The column joints are threaded assemblies at both ends, with 7/16-inch external threads on one end and 3/16-inch internal threads on the other end (standardized at home and abroad). The 7/16-inch external thread is connected to the 1/4-inch column tube (Φ6.35mm) and placed in the middle for sealing. The 3/16″ internal thread is connected to the 1/16″ (Φ 1.57mm) connecting tube, and a pressure ring is placed in the middle for the seal of the column joint.
In order to minimize the dead volume outside the column, when installing the HPLC columns, use a Φ1.57mm connecting tube to insert the hollow screw into the ring, and then tighten the hollow screw. The pressure ring is pressed and deformed by the hollow screw and then hung on the connecting pipe (the length of the pipe exposed after the connecting pipe passes through the pressure ring should be strictly controlled to 2.5 mm long or other fixed sizes).
In the column joints at both ends, a stainless steel filter (or strainer) is placed at each end of the HPLC column tube to block the column packing from being washed out of the column by the mobile phase. Each component of the empty column is made of 316# stainless steel, which can withstand the general solvent effect.
However, since the chloride-containing solvent is corrosive to it, it should be noted that the solvent and the connecting tube cannot be stored for a long time to avoid corrosion.
HPLC Column Characteristics
HPLC columns are widely used in many fields, whose column efficiency, capacity, permeability characteristics, and service life are very important. After using for a period of time, there will be changes such as column pressure increase, column efficiency decrease, etc. If no measures are taken, the service life of HPLC columns will be shortened, the working efficiency will be affected, and some economic losses will be caused.
Features of HPLC columns
1. Suitable for separation; 2. Enhance retention ability; 3. Unique selectivity and excellent separation degree; 4. Suitable for the analysis of acid and alkali compounds.
The purity of silica gel is crucial for the quality of HPLC columns because silica gel with a smooth surface and uniform pore size have higher mechanical strength and better permeability, which are necessary conditions for extending the service life of the chromatographic column.
Selectivity and separation degree of HPLC columns
Under the condition of the same specific surface area, the higher the carbon load of the chromatographic column, the higher the bonding phase density, the stronger the selectivity and separation degree of the complex mixed samples will be.