Sample injection in liquid chromatography

Most important factors in injection are precision, accuracy and carryover. They are effected by the injection technique and equipment and for manual injection also by the user.

In the load position a sample loop is filled with sample while the system is equillibrating. When turning to the inject position, the sample loop is switched to the high pressure part of the HPLC system. The flow delivered by the pump flows through the loop and feeds the sample onto the column.

Manual injection valves are the most cost-effective option to introduce samples. Normally, valves with 6 ports and 2 positions - for loading and injection - are used.

The simplest way to inject your sample into the system. Use a manual injection valve and choose from a large range of different sample loops, available for different applications. 

For analytical HPLC, our valves feature a wide back pressure range of up to 1200 bar with a 0.3 mm bore size. All valves can be equipped with an automatic valve drive.

For protein purification, the AZURA 2-positions valve is perfect for injection of small sample volumes. Connect 1/16” tubings for flowrates up to 100 ml/min. For higher flowrates use the injection valve for 1/8” tubing. Various sample loops are available. The FPLC injection valve can be integrated or act as a standalone module.

For preparative chromatography, KNAUER offers several injection valves for 1/16‘‘ and 1/8” tubing. The wetted parts are made of stainless steel or PEEK to cover a broad range of applications. Injection can be done either manually via hand lever or automated with a valve drive. 

For automated injection of up to 108 different samples, we recommend to use an autosampler. Autosamplers are specialized for analytical HPLC, preparative LC or FPLC sample injection.

The Autosampler AS 6.1L can inject up to 10 ml per injection. Sample tray temperature control from 4 – 40°C is optional available. It can handle either 30 samples in 10 ml vials or up to 768 samples in well plates. The Autosamplers offer high precision and accuracy. The Autosampler also work with an injection valve and a sample loop, but features several injection modes.

Standalone or integrated in an assistant module ASM 2.1L: The compact pump AZURA P4.1S is perfect for feed injection or for injection of larger sample volumes. Repetitive sample injections by using the pump for automated sample loop filling.
Do you have many samples? You can extend your configuration with additional valves each for up to 8 samples.
Our lab experts have designed different pump specifications according to the desired application. We will help you to find your perfect set up. We can even test your application in our lab, to provide you a verified product suggestion. Do not hesitate to contact us.

For preparative chromatography, we recommend a sample pump with 10 and 50 ml exchangeable pump head. The pump heads are available in stainless steel or ceramics.

Flow rate range:

• 0.01 – 50 ml/min (50 ml pump head)
• 0.001 – 10 ml/min (10 ml pump head)

• 1 – 40 ml/min (50 ml pump head)
• 0.1 – 8 ml/min (10 ml pump head)