2-Position Valves
Wide range of valves for injection and column selection
Flow Rate Range
up to 3000 ml/min depending on bore size and capillary connection
Function
Sample injection, Column selection, Bypass
Application area
From analytical to prep with 1/16", 1/8", 1/4" connection
Wetted Material
DLC coated stainless steel for high pressure applications, PEEK for biocompatibility
Internal volume
0.3 - 4.0 mm bore size
Port Number
4, 6, 8, 10
Max. Pressure
up to 1200 bar/ 17400 psi
Innovative
Patented Breakfree technology for truely pressureless switching at any flow rate
HPLC / UHPLC / FPLC valves
Valves for eluent selection, sample injection, column selection and more.
Valves are ubiquitous in all HPLC and UHPLC applications. They act like a switch and can control the flow path of the chromatography system in various ways. Therefore, valves are indispensable for eluent selection, sample injection, column selection, and fractionation as well as any switching task.
KNAUER valves are designed for a wide range of chromatographic and dosing applications. Flexibility is provided by choice of different materials and sizes as well as drivers for various software packages. Valves are driven either manually or automatically through a valve drive.
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Applications for 2-Position Valves
KNAUER AZURA® V 4.1 Valves can perform various tasks
Sample Injection
The probably most often used application of a valve in HPLC is the introduction of a sample into the system. No matter if an autosampler, an automated valve or a manual injection valve is used, the principle is the same when injection via a sample loop is performed. Most often, a 2-position valve with 6 ports is used. The sample loop is installed between two of the ports while the others are reserved for connection to the HPLC pump, the HPLC column, the sample injection and a waste line. In position 1, sample is loaded via into the sample loop. Excess volume exits to the waste line. In position 2, the sample is injected via the pump from the loop onto the column.
Column selection
2 Position valves can also be used as a cost-effective solution for column selection valves. A standard 6-Port two position valve is already a good choice. It allows to select between two columns without changing capillary connections. In position 1, the flow of the HPLC pump is directed via column A to the detector. In position 2, the flow is directed via column B.
Sample injection and column backflushing
This configuration allows to reduce analysis time for sample with late-eluting compounds, which are not relevant for sample analysis. In position 1, the sample is injected onto the column. After relevant compounds were separated and detected, the valve is switched to position 2. Undesired, strongly retarded compounds are backflushed and removed to prepare the column for the next separation. Also, in this position the sample loop is loaded.
High-throughput sample loading
When an 8 port two position valve is used, the application range can be expanded. This configuration allows high-throughput analysis as sample loading and injection are parallized. In position 1, the sample is loaded to sample loop B, while sample from loop A is injected. In position 2, the sample of sample loop B is injected onto the column. In parallel, sample can be loaded again into loop A.
Automated Valves
Automated valves are mounted on an AZURA® VU 4.1 Valve Unifier and controlled either via Chromatography software or the VU 4.1 display. The user chooses between manually filling the sample loop using a syringe or automatically filling the sample loop with an additional pump.
Automated Valves
Automated valves are mounted on an AZURA® VU 4.1 Valve Unifier and controlled either via Chromatography software or the VU 4.1 display. The user chooses between manually filling the sample loop using a syringe or automatically filling the sample loop with an additional pump.
Automated Valves
Automated valves are mounted on an AZURA® VU 4.1 Valve Unifier and controlled either via Chromatography software or the VU 4.1 display. The user chooses between manually filling the sample loop using a syringe or automatically filling the sample loop with an additional pump.
Automated Valves
Automated valves are mounted on an AZURA® VU 4.1 Valve Unifier and controlled either via Chromatography software or the VU 4.1 display. The user chooses between manually filling the sample loop using a syringe or automatically filling the sample loop with an additional pump.
Automated Valves
Automated valves are mounted on an AZURA® VU 4.1 Valve Unifier and controlled either via Chromatography software or the VU 4.1 display. The user chooses between manually filling the sample loop using a syringe or automatically filling the sample loop with an additional pump.
