Rheodyne 7725 Injection Valve for Series 200 Autosampler

Patented Make-Before-Break (MBB™) architecture virtually eliminates transient pressure shocks for extended column life Available in stainless steel and PEEK for sample compatibility Zero sample loss Wide 30° port angles for easy access Small diameter internal flow paths assure minimal dispersion The Model 7725 and 7725i are Rheodyne's most advanced sample injectors for analytical HPLC. They can inject from 1 mL to 5 mL with high accuracy and precision. These versatile injectors can use either of two methods for loading the sample loop. The partial filling method uses the syringe to measure the sample volume. It lets you vary volume easily without having to change the loop, and it does not waste any sample. Any amount up to half the loop volume can be loaded. The amount injected into the column is the exact volume dispensed from the syringe. The complete filling method uses the loop to measure the volume. It lets you load the loop without having to read syringe calibrations carefully. Excess sample is required to completely flush mobile phase from the loop. The amount injected is the volume of the loop. Flow switching occurs at a flat interface between a polymeric rotor seal and a ceramic stator face. This combination provides long seal life. In a clean system, the 7725 typically can make more than 30,000 injections before requiring replacement of the rotor seal.