9725I - 2/6 Syr Load Inj w/ Pos Sensor

The IDEX Rheodyne Model 9725i is a PEEK-constructed six-port manual HPLC injector designed for applications requiring a metal-free flow path and reliable injection confirmation. Built on the proven Rheodyne manual valve architecture, the 9725i incorporates an integrated position sensing switch that provides electronic confirmation of the injector position for system synchronization and data acquisition workflows.

The valve body and wetted flow path are constructed from PEEK (polyether ether ketone), providing excellent chemical resistance and eliminating metal contact with the sample stream. This biocompatible design is ideal for chromatography workflows involving proteins, peptides, biomolecules, ion chromatography, and trace-metal sensitive analytes where stainless steel surfaces may cause adsorption or catalytic effects.

The Model 9725i includes a front-mounted needle port for direct loop loading, allowing operators to perform quick and reproducible manual injections. A 20 µL sample loop is typically supplied with the injector, providing dependable injection volumes for routine analytical HPLC methods.

The injector operates using Make-Before-Break (MBB) valve switching, ensuring continuous mobile phase flow as the handle rotates between the LOAD and INJECT positions. This design prevents pressure disturbances and maintains stable chromatographic baselines during injection events.

Engineered for durability and chemical compatibility, the valve supports operating pressures up to 345 bar / 5000 psi and temperatures up to 80°C, making it suitable for demanding analytical HPLC workflows while maintaining the benefits of a fully metal-free flow path.

Key Features

• PEEK valve construction for metal-free, biocompatible chromatography
• Six-port manual injector for analytical HPLC systems
• Integrated position sensing switch for valve status feedback
• Front needle port for direct loop loading
• Make-Before-Break switching for uninterrupted mobile phase flow
• Maximum operating pressure of 345 bar / 5000 psi
• Maximum operating temperature of 80°C
• Supplied with a standard 20 µL sample loop
• Excellent chemical resistance to aggressive solvents and buffers

Advantages of PEEK Construction

The PEEK construction used in the Model 9725i eliminates metal surfaces within the sample flow path. This reduces the risk of analyte adsorption, metal contamination, or catalytic degradation that can occur with stainless steel components. As a result, the injector is particularly well suited for biopharmaceutical analysis, ion chromatography, protein analysis, and other bioinert LC applications.

PEEK materials also provide excellent compatibility with common HPLC solvents such as acetonitrile, methanol, water, and buffered mobile phases, allowing the valve to operate reliably across a wide range of chromatographic conditions.

Injection Methods

The Model 9725i supports both complete loop filling and partial loop filling injection techniques. Complete loop filling provides the highest injection precision because the sample loop defines the injected volume, while partial loop filling allows smaller sample volumes when sample availability is limited.

Position Sensing Capability

The built-in position sensing switch differentiates the 9725i from the standard 9725 model. This switch confirms whether the injector is in the LOAD or INJECT position, allowing chromatography systems or external electronics to detect injection events and synchronize data acquisition.

Maintenance and Serviceability

The injector is designed for long operational life with field-replaceable components including the rotor seal and stator face assembly. Dedicated service kits such as RheBuild™ maintenance kits are available to restore valve performance and extend service life.

Typical Applications

The Model 9725i is ideal for laboratories requiring a metal-free manual HPLC injector with electronic position feedback. It is commonly used in biopharmaceutical research, protein analysis, ion chromatography, environmental testing, and analytical LC workflows where chemical compatibility, injection repeatability, and system synchronization are important.