The model 7125 valve is highly dependable and versatile. A variety of sample loop sizes are available and easily exchanged. Most commonly, users will find that one loop size accommodates the majority of their applications. The model 7125 is syringe-loaded through the face of the injector. It is recommended that the sample loop either be overfilled by three times the loop volume, or partially filled to less than 50% of capacity when loading sample by syringe. Although the model 7125 valve can be rated to 7000 psi, BASi adjusts valves to 5000 psi to extend seal life. Optional stainless steel loop sizes (5 µL to 5 mL) Are available.

A major advantage of UniJet microbore columns is the design that permits direct connection of the column to the injector and an electrochemical cell. To prevent grounding problems with the detector, the valve must be electrically isolated from the column and attached cell. The BASi custom valve uses a plastic (PEEK) stator to achieve this isolation. It also incorporates low dispersion design features that are optimal for microbore applications and equally useful for conventional LC. This valve is a good choice if you plan to upgrade to microbore in the future.

Smaller flow channels in the custom valve produce less dispersion when compared to the 7125 valve. This results in better chromatographic resolution in a system using a 1 mm I.D. column and low dispersion detector, such as the BASi LCEC cell. The valve has a built-in sensing switch which signals an external device (e.g. integrator, workstation) that an injection has been made. Use peek sample loops, MF-4145 — MF-4150, with this injector.