The injection valve (P/N 057968) is a 2-position, electrically-activated Rheodyne™ valve. A 25-µL sample loop (P/N 042857) is included in the Dionex Inuvion IC System Ship Kit. The injection valve shares the same part number (and is identical to) the 6-port auxiliary valve. However, this valve is used and installed differently, depending on whether it will function as an injection valve or an auxiliary valve.

The valve has two operating positions: Load and Inject (see the following image).

Figure Injection valve flow schematics (red indicates the active path)

Eluent flows through the Load or Inject path, depending on the valve position.

  • Load position: Sample is loaded into the sample loop, where it is held until injection. Eluent flows from the pump, through the valve, and to the column, bypassing the sample loop. Sample flows from the syringe or automated sampler line (if installed), through the valve, and into the sample loop. Excess sample flows out to waste.
  • Inject position: Sample is swept to the column for analysis. Eluent flows from the pump, through the sample loop, and on to the column, carrying the contents of the sample loop with it. To inject samples, see Loading and injecting samples.

The following image shows the injection valve connections. The injection valve is plumbed at the factory with all tubing and fittings for connection to the pump, injection port, column, and waste. A 25-µL PEEK sample loop (P/N 042857) is installed between ports L (1) and L (4). Thermo Fisher Scientific offers sample loops in various sizes. If necessary, replace the pre-installed 25-µL loop with a loop that has a different sample injection volume.

Figure Injection valve connections