8125 - 2/6 Syringe Load Micro Inj, SS

The Model 8125 is a six-port manual micro-scale sample injector designed for precise, low-dispersion sample introduction in HPLC and related analytical workflows. This compact valve features a built-in needle port in the handle for direct sample loading, making it well suited for laboratories that need reliable manual injections with minimal dead volume and strong reproducibility.

Engineered for demanding chromatography applications, the Model 8125 combines high-pressure performance with micro-scale flow geometry. Five stator ports use a dual-size port design that accommodates both 0.5 mm (0.020") and 1/16" OD tubing, while Port 3 is optimized for 1/16" OD tubing that bottoms out in the port for a low-dispersion column connection. This design helps maintain tight, efficient flow paths where injection accuracy and peak shape matter most.

The valve is rated to 48 MPa (483 bar, 7000 psi) and up to 80°C, making it appropriate for a wide range of routine and higher-pressure analytical methods. Wetted surfaces are stainless steel and an inert polymer, and the valve also includes a built-in position sensing switch for systems that benefit from valve status monitoring.

Key Features

• Six-port manual micro-scale injector with integrated needle port
• High-pressure operation up to 48 MPa / 7000 psi
• Maximum operating temperature of 80°C
• Dual-size stator port design for flexible tubing connections
• Low-dispersion Port 3 design for 1/16" OD tubing
• Built-in position sensing switch
• Standard 5 µL sample loop included

Supplied with the Valve

The Model 8125 is supplied with RheFlex® stainless steel fitting sets for all ports, plus the accessories needed for installation and operation. Included items consist of hex keys, wrench, needle port cleaner, vent tubes, mounting screws, and a 5 µL sample loop.

Designed for Precision Manual Injection

Model 8125 supports multiple manual loading approaches, including complete loop filling, partial loop filling, and loading by suction. Complete loop filling provides the highest precision by setting the injected volume with the sample loop, while partial loop filling is useful when sample quantity is limited and the syringe determines injection volume. This flexibility makes the valve a practical option for laboratories handling both routine samples and limited-volume analytical work.

For low-dispersion performance, the manual recommends 0.5 mm (0.020") OD tubing for the sample loop. At the same time, the optimized geometry of Port 3 allows 1/16" OD tubing for the column connection without creating a cavity that would otherwise increase dispersion. This helps maintain efficient transfer from injector to column and supports cleaner chromatographic performance.

Maintenance and Serviceability

The valve is designed for service with replaceable wear components, including the rotor seal, isolation seal, and stator face assembly. A dedicated RheBuild® Kit (8125-999) is available for maintaining valve performance and includes the major replacement parts, tools, and instructions needed for routine rebuilds.

Applications

The Model 8125 is a strong fit for chromatography users who need a manual injector with micro-scale flow paths, high-pressure capability, and direct needle-port loading. It is especially useful in analytical environments where minimizing dispersion, maintaining precise sample introduction, and supporting flexible loop-loading methods are important to overall method performance.