9725 - 2/6 Syr Load Inj, w/MBB, PK

The IDEX Rheodyne Model 9725 is a six-port manual HPLC injector constructed from PEEK (polyether ether ketone), designed for chromatographic applications where metal-free flow paths and high chemical resistance are required. The PEEK valve body and internal wetted components provide excellent compatibility with aggressive solvents, bioanalytical samples, and metal-sensitive analytes.

Unlike traditional stainless steel injectors, the Model 9725 offers a biocompatible and corrosion-resistant flow path. This makes the valve particularly useful for LC workflows involving proteins, peptides, biomolecules, ion chromatography, and trace-metal sensitive analyses where metal surfaces can introduce contamination or adsorption effects.

The injector features a front-mounted needle port for direct loop loading, enabling fast and reproducible manual injections. A 20 µL sample loop is typically supplied as standard, allowing consistent injection volumes for analytical HPLC methods.

The Model 9725 uses Make-Before-Break (MBB) valve architecture, ensuring continuous mobile phase flow as the injector handle rotates between the LOAD and INJECT positions. This switching design prevents pressure shocks and maintains stable chromatographic baselines during injection events.

The valve is rated for operating pressures up to 345 bar / 5000 psi and temperatures up to 80°C, making it suitable for a wide range of analytical HPLC applications while maintaining the benefits of a metal-free flow path.

Key Features

• PEEK valve construction for metal-free, biocompatible chromatography
• Six-port manual injector for analytical HPLC systems
• 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

Advantages of PEEK Construction

The PEEK construction of the Model 9725 eliminates metal contact within the flow path, reducing the risk of analyte adsorption or catalytic degradation that can occur with stainless steel components. This design is particularly valuable in bioanalytical, pharmaceutical, and ion chromatography workflows where maintaining analyte integrity is critical.

PEEK also provides excellent resistance to common HPLC solvents such as acetonitrile, methanol, buffers, and salt solutions, allowing the injector to operate reliably across a wide range of chromatographic conditions.

Injection Methods

The Model 9725 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.

Maintenance and Serviceability

The injector is designed for long service life and field maintenance. Wear components such as the rotor seal and stator face assembly can be replaced using dedicated service kits to restore valve performance and extend operational lifetime.

Typical Applications

The Model 9725 is ideal for laboratories requiring a metal-free manual HPLC injector with excellent chemical resistance and reproducible sample introduction. It is commonly used in biopharmaceutical analysis, ion chromatography, protein analysis, trace-metal sensitive workflows, and other bioinert LC applications.