Glass columns high-pressure resistant

Fig. 1. Schematic diagram of a high-pressure resistant glass column system.

The column length varies from 3 to 30 cm, the inner diameter from 1 to 10 mm. Columns are made of very resistant materials to withstand high pressures (<40 MPa) Most commonly, a stainless steel or heavy-walled glass tube is inserted into a metal tube. Columns are packed with a solid material of particle size <10 pm (spherical and nonporous microglass beads or polymer particles). A guard column is usually placed before the column to remove suspended particles from solvents, as well as certain sample constituents that could irreversibly bind to the stationary phase. 

The equipment used in HPIEC is different from that used in CIEC. The columns, valves, and pipes are exposed to high pressures. This requires them to be not only corrosion resistant to acids, bases, and other chemical agents, but they also need to be pressure resistant. Because of this, the materials used in their construction are required to be of higher quality than the material used to construct the CIEC devices. The devices, e.g., the column, valves, pipes, sieves, pressure vessels, and pressure gauges used by the authors, were primarily made of special stainless steel. Some junctions were made of polytetrafluoroethylene plastic. Usually the last column of a system of columns was made of glass so as to permit observation of the separation affected. 

With glass columns, however, no high-speed separations can be expected on long columns because of their limited pressure resistance. 

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