Liquid Chromatography - The Sample Valve 3
As a consequence of the high pressures that must be tolerated, LC sample valves are usually made from stainless steel. The exception to the use of stainless steel will arise in biochemical applications where the materials of construction may need to be bio-compatible. In such cases the valves may be made from titanium or some other appropriate bio-compatible material. It should be stressed that only those surfaces that actually come in contact with the sample need to be bio-compatible and the major parts of the valve can still be manufactured from stainless steel. The actual structure of the valve varies a little from one manufacturer to another but all are modifications of the basic sample valve shown in figure 14.
Courtesy of Valco Instruments Inc.
Figure 14. A Simple Form of the LC Sample Valve